3The Bayes Premium
Lecture 8
Subjective probability theory
• Alias paradox: • We observed usually that A B , D C • BUT, as the v.N-M expected utility function indicates, A B C D A B u(50) 0.1u(250) 0.89u(50) 0.01u(0)
• u (.) is increasing, continuous and bounded.
Risk aversion
• A risk aversion man: xdF ( x ) is as better at least as a lottery with F(x) . • Jenson’s inequality: u ( xdF ( x)) u ( x)dF ( x) • u(.) is concave or strictly concave if the man is (strictly) risk aversion.
0.11u(50) 0.89u(0) 0.1u(250) 0.9u(0) C D
Subjective probability theory
• People will update their subjective probability. • Bayes’ theorem:
P( E | H ) P( H ) P( H | E ) P( E )
Metric
• Example3:Pricing for risk assets
Metric
• Relative risk aversion index:
– The wealth changes in proportion
大学英语写作范文(实用14篇)
大学英语写作范文1Learning English at college is different from learning English at middle school. In middle school, we learn English mainly for the entrance examination for college, while the purpose of learning English at college is quite different. We study foreign languages now to improve our ability to work in the future and especially to communicate with foreiguers.How can we learn English well at college? Firstly, you should try your best to enlarge your vocabulary. Only in this way can you read more smoothly and understand others well. Secondly, you should pay more attention to the listening and speaking ability in learning English. While talking with foreigners, if you cant understand them, and do not know how to express yourself, the talking will be very difficult. And the last point is that you should improve your English whenever and wherever you can.Obviously, there is still a long way for us to go to learn English well. As a proverb says, Never too old to learn. There are so many methods to learn English. So long as you keep on studying, your English will surely be improved.大学英语写作范文2In general, knowledge gained from books has a wider range than that gained from experience. We now live in a world that typophile is no longer exorbitant, and that printed matters are readily available. In libraries, we can learn nearly everything only if we have already acquired basic reading skills, philosophy, history, literature, physics, mathematics, chemicals, biology, geography, anthropology, and the list will go on. Unlike the experience of an individual that is limited by the range of that individual, books seem to have almost no limitation. Sitting in the local library, we virtually can travel everywhere through an interesting geographic encyclopedia, and certainly, with nearly no expense at all. On the other hand, it can be argued that sometimes knowledge gained from experience is much deeper and more comprehensive than that gained from books. It is quite true that not every thing is contained in books. How to deal with personal finance, how to cope with current social trends, even how to most effectively organize our own mind, and numerous other things can seldom be found thoroughly and comprehensively discussed in books, we have to gain the knowledge by our own experience. And the sad news is that even some knowledge that is contained in books usually needs further comprehension, mainly through experience. As to which source is more important, the answers vary. Some knowledge can be acquired only through books. It's hard to imagine we can have a good understanding of history without reading books. On the other hand, some knowledge can be obtained only through experience. When we try to learn to swim, merely a detailed manual of swimming skills, even abundantly filled with illustrations, is at most useless. We have to jump into the water and then gain the knowledge with experience. We have to use books and experience as source simultaneously to get what we want to know. Take learning physics for example, both books and experiences are equally important sources, and examples as such are numerous. Therefore, I think whether one source is more important than the other depends on circumstances.在一般情况下，从书中获得的知识，有一个更广泛的范围比从经验中获得的。
2003年5月北美精算第四门考试试题
Course 4Fall 2003 Society of Actuaries**BEGINNING OF EXAMINATION** 1. You are given the following information about a stationary AR(2) model:=.(i) ρ105(ii) ρ201=.Determine φ2.(A) –0.2(B) 0.1(C) 0.4(D) 0.7(E) 1.0(i) Losses follow a loglogistic distribution with cumulative distribution function:F x x x b g b g b g =+//θθγγ1(ii)The sample of losses is:10 35 80 86 90 120 158 180 200 210 1500Calculate the estimate of θ by percentile matching, using the 40th and 80th empirically smoothed percentile estimates.(A) Less than 77(B) At least 77, but less than 87(C) At least 87, but less than 97(D) At least 97, but less than 107(E) At least 107(i) The number of claims has a Poisson distribution.(ii) Claim sizes have a Pareto distribution with parameters θ=0.5 and α=6.(iii) The number of claims and claim sizes are independent.(iv) The observed pure premium should be within 2% of the expected pure premium 90% of the time.Determine the expected number of claims needed for full credibility.(A) Less than 7,000(B) At least 7,000, but less than 10,000(C) At least 10,000, but less than 13,000(D) At least 13,000, but less than 16,000(E) At least 16,0004. You study five lives to estimate the time from the onset of a disease to death. The times todeath are:2 3 3 3 7Using a triangular kernel with bandwidth 2, estimate the density function at 2.5.(A) 8/40(B) 12/40(C) 14/40(D) 16/40(E) 17/405. For the model i i i Y X αβε=++, where 1,2,...,10i =, you are given:(i) X i i =R S T1, if the th individual belongs to a specified group 0, otherwise(ii) 40 percent of the individuals belong to the specified group.(iii) The least squares estimate of β is β=4.(iv) ()2ˆˆ92i i Y X αβ−−=∑Calculate the t statistic for testing H 00:β=.(A) 0.9(B) 1.2(C) 1.5(D) 1.8(E) 2.1(i) Losses follow a Single-parameter Pareto distribution with density function:()()1,1f x x xαα+=>, 0 < α < ∞ (ii) A random sample of size five produced three losses with values 3, 6 and 14, and twolosses exceeding 25.Determine the maximum likelihood estimate of α.(A) 0.25(B) 0.30(C) 0.34(D) 0.38(E) 0.42(i) The annual number of claims for a policyholder has a binomial distribution withprobability function:()()221x x p x q q q x −⎛⎞=−⎜⎟⎝⎠, x = 0, 1, 2(ii) The prior distribution is:()34,01q q q π=<<This policyholder had one claim in each of Years 1 and 2.Determine the Bayesian estimate of the number of claims in Year 3.(A) Less than 1.1(B) At least 1.1, but less than 1.3(C) At least 1.3, but less than 1.5(D) At least 1.5, but less than 1.7(E) At least 1.78. For a sample of dental claims 1210,,...,x x x , you are given:(i) 23860 and 4,574,802i i x x ==∑∑(ii) Claims are assumed to follow a lognormal distribution with parameters µ and σ.(iii)µ and σ are estimated using the method of moments.Calculate ∧ for the fitted distribution.(A) Less than 125(B) At least 125, but less than 175(C) At least 175, but less than 225(D) At least 225, but less than 275(E) At least 2759. You are given:(i)Y tij is the loss for the j th insured in the i th group in Year t . (ii)ti Y is the mean loss in the i th group in Year t . (iii)X j i j i ij =R S T0, if the th insured is in the first group (=1)1, if the th insured is in the second group (=2) (iv)21ij ij ij ij Y Y X δφθε=+++, where 1,2i = and 1,2,...,j n = (v)Y Y Y Y 2122111230374041====,,, (vi) ˆ0.75φ=Determine the least-squares estimate of θ.(A) 5.25(B) 5.50(C) 5.75(D) 6.00(E) 6.2510. Two independent samples are combined yielding the following ranks:Sample I: 1, 2, 3, 4, 7, 9, 13, 19, 20Sample II: 5, 6, 8, 10, 11, 12, 14, 15, 16, 17, 18You test the null hypothesis that the two samples are from the same continuous distribution.The variance of the rank sum statistic is:()112n m n m ++Using the classical approximation for the two-tailed rank sum test, determine the p -value.(A) 0.015(B) 0.021(C) 0.105(D) 0.210(E) 0.420(i) Claim counts follow a Poisson distribution with mean θ. (ii) Claim sizes follow an exponential distribution with mean 10θ. (iii) Claim counts and claim sizes are independent, given θ. (iv) The prior distribution has probability density function:b g=5, θ>1πθθCalculate Bühlmann’s k for aggregate losses.(A) Less than 1(B) At least 1, but less than 2(C) At least 2, but less than 3(D) At least 3, but less than 4(E) At least 4(i) A survival study uses a Cox proportional hazards model with covariates Z 1 and Z 2,each taking the value 0 or 1.(ii) The maximum partial likelihood estimate of the coefficient vector is:, .,.ββ12071020e j b g=(iii) The baseline survival function at time t 0 is estimated as .S t 0065b g =.Estimate S t 0b gfor a subject with covariate values 121Z Z ==.(A) 0.34(B) 0.49(C) 0.65(D) 0.74(E) 0.84(i) Z 1 and Z 2 are independent N(0,1) random variables.(ii) a , b , c , d , e , f are constants.(iii) Y a bZ cZ X d eZ f Z =++=++1212 andDetermine ()E Y X .(A) a(B) ()()a b c X d ++−(C) a be cf X d ++−b gb g(D) a be cf e f +++g d /22(E) a be cf e f X d +++−g d g/22(i) Losses on a company’s insurance policies follow a Pareto distribution with probabilitydensity function:()(),0f x x x θθθ=<<∞+(ii) For half of the company’s policies θ=1, while for the other half θ=3.For a randomly selected policy, losses in Year 1 were 5.Determine the posterior probability that losses for this policy in Year 2 will exceed 8.(A) 0.11(B) 0.15(C) 0.19(D) 0.21(E) 0.2715. You are given total claims for two policyholders:Year1 2 3 4PolicyholderX 730 800 650 700Y 655 650 625 750Using the nonparametric empirical Bayes method, determine the Bühlmann credibilitypremium for Policyholder Y.(A) 655(B) 670(C) 687(D) 703(E) 71916. A particular line of business has three types of claims. The historical probability and thenumber of claims for each type in the current year are:Type HistoricalProbabilityNumber of Claimsin Current YearA 0.2744 112B 0.3512 180C 0.3744 138You test the null hypothesis that the probability of each type of claim in the current year is the same as the historical probability.Calculate the chi-square goodness-of-fit test statistic.(A) Less than 9(B) At least 9, but less than 10(C) At least 10, but less than 11(D) At least 11, but less than 12(E) At least 1217. Which of the following is false?(A) If the characteristics of a stochastic process change over time, then the process isnonstationary.(B) Representing a nonstationary time series by a simple algebraic model is often difficult.(C) Differences of a homogeneous nonstationary time series will always be nonstationary.(D) If a time series is stationary, then its mean, variance and, for any lag k, covariancemust also be stationary.(E) If the autocorrelation function for a time series is zero (or close to zero) for all lagsk>0, then no model can provide useful minimum mean-square-error forecasts offuture values other than the mean.18. The information associated with the maximum likelihood estimator of a parameter θ is 4n,where n is the number of observations.Calculate the asymptotic variance of the maximum likelihood estimator of 2θ.(A) 12n(B) 1n(C) 4n(D) 8n(E) 16n19. You are given:(i) The probability that an insured will have at least one loss during any year is p.(ii) The prior distribution for p is uniform on []0,0.5.(iii) An insured is observed for 8 years and has at least one loss every year.Determine the posterior probability that the insured will have at least one loss during Year 9.(A) 0.450(B) 0.475(C) 0.500(D) 0.550(E) 0.62520. At the beginning of each of the past 5 years, an actuary has forecast the annual claims for agroup of insureds. The table below shows the forecasts (X) and the actual claims (Y). Atwo-variable linear regression model is used to analyze the data.t X t Y t1 475 2542 254 4633 463 5154 515 5675 567 605You are given:(i) The null hypothesis is0:0,1Hαβ==.(ii) The unrestricted model fit yields ESS = 69,843.Which of the following is true regarding the F test of the null hypothesis?(A) The null hypothesis is not rejected at the 0.05 significance level.(B) The null hypothesis is rejected at the 0.05 significance level, but not at the 0.01 level.(C) The numerator has 3 degrees of freedom.(D) The denominator has 2 degrees of freedom.(E) TheF statistic cannot be determined from the information given.21-22. Use the following information for questions 21 and 22.For a survival study with censored and truncated data, you are given:Time (t) Number at Riskat Time t Failures at Time t1 30 52 27 93 32 64 25 55 20 4 21. The probability of failing at or before Time 4, given survival past Time 1, is31q.Calculate Greenwood’s approximation of the variance of 31 q.(A) 0.0067(B) 0.0073(C) 0.0080(D) 0.0091(E) 0.010521-22. (Repeated for convenience) Use the following information for questions 21 and 22.For a survival study with censored and truncated data, you are given:Time (t) Number at Riskat Time t Failures at Time t1 30 52 27 93 32 64 25 55 20 4 22. Calculate the 95% log-transformed confidence interval for H3b g, based on the Nelson-Aalenestimate.(A) (0.30,0.89)(B) (0.31,1.54)(C) (0.39,0.99)(D) (0.44,1.07)(E) (0.56,0.79)(i) Two risks have the following severity distributions:Amount of Claim Probability of ClaimAmount for Risk 1Probability of ClaimAmount for Risk 2250 0.5 0.72,500 0.3 0.260,000 0.2 0.1(ii) Risk 1 is twice as likely to be observed as Risk 2.A claim of 250 is observed.Determine the Bühlmann credibility estimate of the second claim amount from the same risk.(A) Less than 10,200(B) At least 10,200, but less than 10,400(C) At least 10,400, but less than 10,600(D) At least 10,600, but less than 10,800(E) At least 10,800(i) A sample x x x 1210,,,… is drawn from a distribution with probability density function:1211exp()exp(), 0[]x x x θθσσ−+−<<∞(ii)θσ>(iii) x x i i ==∑∑15050002 andEstimate θ by matching the first two sample moments to the corresponding population quantities.(A) 9(B) 10(C) 15(D) 20(E) 2125. You are given the following time-series model:115.028.0−−−++=t t t t y y εεWhich of the following statements about this model is false?(A) 10.4ρ=(B) 1,2,3,4,....k k ρρ<=(C) The model is ARMA(1,1).(D) The model is stationary.(E) The mean, µ, is 2.26. You are given a sample of two values, 5 and 9.You estimate Var(X ) using the estimator g (X 1, X 2) = 21().2i X X −∑Determine the bootstrap approximation to the mean square error of g .(A) 1(B) 2(C) 4(D) 8(E) 1627. You are given:(i) The number of claims incurred in a month by any insured has a Poisson distributionwith mean λ.(ii) The claim frequencies of different insureds are independent.(iii) The prior distribution is gamma with probability density function:()()6100100120efλλλλ−=(iv) Month Number of Insureds NumberofClaims1 100 62 150 83 200 114 300 ?Determine the Bühlmann-Straub credibility estimate of the number of claims in Month 4.(A) 16.7(B) 16.9(C) 17.3(D) 17.6(E) 18.028. You fit a Pareto distribution to a sample of 200 claim amounts and use the likelihood ratio testto test the hypothesis that 1.5α= and 7.8θ=.You are given:(i) The maximum likelihood estimates are α= 1.4 and θ = 7.6.(ii) The natural logarithm of the likelihood function evaluated at the maximum likelihoodestimates is −817.92.(iii) ()ln 7.8607.64i x +=∑Determine the result of the test.(A) Reject at the 0.005 significance level.(B) Reject at the 0.010 significance level, but not at the 0.005 level.(C) Reject at the 0.025 significance level, but not at the 0.010 level.(D) Reject at the 0.050 significance level, but not at the 0.025 level.(E) Do not reject at the 0.050 significance level.29. You are given:(i) The model is Y X i i i =+βε, i = 1, 2, 3.(ii)i X i Var εi b g11 12 2 93 316 (iii)The ordinary least squares residuals are εβi i i Y X =−, i = 1, 2, 3.Determine E X X X ,,ε12123d i.(A) 1.0(B) 1.8(C) 2.7(D) 3.7(E) 7.630. For a sample of 15 losses, you are given:(i)Interval Observed Number ofLosses(0, 2] 5(2, 5] 5(5, ∞) 5 (ii) Losses follow the uniform distribution on 0,θb g.Estimate θ by minimizing the function()231j jjjE OO=−∑, where j E is the expected number oflosses in the j th interval andjO is the observed number of losses in the j th interval.(A) 6.0(B) 6.4(C) 6.8(D) 7.2(E) 7.631. You are given:(i) The probability that an insured will have exactly one claim is θ.(ii) The prior distribution of θ has probability density function:πθθθb g=<<3201,A randomly chosen insured is observed to have exactly one claim.Determine the posterior probability that θ is greater than 0.60.(A) 0.54(B) 0.58(C) 0.63(D) 0.67(E) 0.7232. The distribution of accidents for 84 randomly selected policies is as follows:Number of Accidents Number of Policies0 321 262 123 74 45 26 1Total 84 Which of the following models best represents these data?binomial(A) Negativeuniform(B) Discrete(C) Poisson(D) Binomial(E) Either Poisson or Binomial33. A time series yt follows an ARIMA(1,1,1) model with φ107=., θ103=−. and σε210=..Determine the variance of the forecast error two steps ahead.(A) 1(B)5(C) 8(D)10(E) 12(i) Low-hazard risks have an exponential claim size distribution with mean θ. (ii) Medium-hazard risks have an exponential claim size distribution with mean 2θ. (iii) High-hazard risks have an exponential claim size distribution with mean 3θ. (iv) No claims from low-hazard risks are observed.(v) Three claims from medium-hazard risks are observed, of sizes 1, 2 and 3. (vi) One claim from a high-hazard risk is observed, of size 15.Determine the maximum likelihood estimate of θ.(A) 1(B) 2(C) 3(D) 4(E) 5(i)partial X =pure premium calculated from partially credible data(ii)partial E X µ⎡⎤=⎣⎦ (iii) Fluctuations are limited to ±k µ of the mean with probability P(iv) Z = credibility factorWhich of the following is equal to P ?(A) partial Pr k X k µµµµ⎡⎤−≤≤+⎣⎦(B) partial Pr +Z k Z X Z k µµ⎡⎤−≤≤⎣⎦(C) partial Pr +Z Z X Z µµµµ⎡⎤−≤≤⎣⎦(D) ()partial Pr 111k Z X Z k µ⎡⎤−≤+−≤+⎣⎦(E) ()partial Pr 1k Z X Z k µµµµµ⎡⎤−≤+−≤+⎣⎦36. For the model 1223344i i i i i Y X X X ββββε=++++, you are given:(i) N = 15(ii)(iii) ESS =28282.Calculate the standard error of 32ˆˆββ−.(A) 6.4(B) 6.8(C) 7.1(D) 7.5(E) 7.837. You are given:Assume a uniform distribution of claim sizes within each interval.Estimate E X X 2150c h g −∧.(A)Less than 200(B)At least 200, but less than 300(C)At least 300, but less than 400(D)At least 400, but less than 500(E)At least 50038. Which of the following statements about moving average models is false?(A) Both unweighted and exponentially weighted moving average (EWMA) models canbe used to forecast future values of a time series.(B) Forecasts using unweighted moving average models are determined by applying equalweights to a specified number of past observations of the time series.(C) Forecasts using EWMA models may not be true averages because the weights appliedto the past observations do not necessarily sum to one.(D) Forecasts using both unweighted and EWMA models are adaptive because theyautomatically adjust themselves to the most recently available data.(E) Using an EWMA model, the two-period forecast is the same as the one-periodforecast.39. You are given:(i) Each risk has at most one claim each year.(ii)Type of Risk Prior Probability Annual Claim ProbabilityI 0.7 0.1II 0.2 0.2III 0.1 0.4 One randomly chosen risk has three claims during Years 1-6.Determine the posterior probability of a claim for this risk in Year 7.(A) 0.22(B) 0.28(C) 0.33(D) 0.40(E) 0.4640. You are given the following about 100 insurance policies in a study of time to policysurrender:(i) The study was designed in such a way that for every policy that was surrendered, ar, is always equal to 100.new policy was added, meaning that the risk set,j(ii) Policies are surrendered only at the end of a policy year.(iii) The number of policies surrendered at the end of each policy year was observed to be:1 at the end of the 1st policy year2 at the end of the 2nd policy year3 at the end of the 3rd policy yearn at the end of the n th policy year(iv) The Nelson-Aalen empirical estimate of the cumulative distribution function at time n, F, is 0.542.)(ˆnWhat is the value of n?(A) 8(B) 9(C) 10(D) 11(E) 12**END OF EXAMINATION**Course 4, Fall 2003PRELIMINARY ANSWER KEYQuestion # Answer Question # Answer 1 A21 A 2 E22 D 3 E23 D 4 B24 D 5 D25 E 6 A26 D 7 C27 B 8 D28 C 9 E29 B 10 D30 E 11 C31 E 12 A32 A 13 E33 B 14 D34 B 15 C35 E 16 B36 C 17 C37 C 18 B38 C 19 A39 B 20 A40 E。
2023年初一上半年9月月考英语试卷(江苏省南京市南京外国语学校)
单选题Which of the following words contain the pronunciation /ɪ/?A.feelB.realC.childrenD.suit【答案】C【解析】句意：下面哪个词包含发音/ɪ/？考查单词语音辨析。
A. feel /fiːl/；B. real /ˈriːl/ ；C. children/ˈtʃɪldrən/；D. suit /suːt/。
故选C。
单选题Which of the underlined letter has a different pronunciation?A.thereB.clothesC.bothD.those【答案】C【解析】句意：下面哪个划线字母发音不同？考查字母语音辨析。
A. there / ð/；B. clothes / ð/；C. both /θ/；D. those/ ð/。
故选C。
单选题The shop ________ open until 10 PM every day. The shopkeeper is very busy.A.doesn’tB.isn’tC.isD.does【答案】B【解析】句意：这个商店每天营业到下午10点，那个店主很忙。
考查系动词辨析。
The shop ________ open句子中的open是形容词表示开着的，所以句子成分分析缺少系动词，要选择be动词；根据句意表示直到晚上10点才关门，直到……才not…until。
故选B。
单选题I like playing ________ guitar in my free time and I join________ guitar lesson at the weekends.A.the; aB.a; theC./; aD.the; the【答案】D【解析】句意：我喜欢在空余时间里弹吉他而且我喜欢周末上吉他课。
考查冠词辨析。
2024年全国硕士研究生招生考试英语一真题考研英语一
2024年全国硕士研究生入学统一考试英语(一)试题Section I Use of EnglishDirections:Read the following text.Choose the best word(s) for each numbered blank and mark A,B,C or D on the ANSWER SHEET.(10 points)There's nothing more welcoming than a door opening for you. 1 the need to be touched to open or close, automatic doors are essential in 2disabled access to buildings and helping provide general3to commercial buildings.Self-sliding doors began to emerge as a commercial product in 1960 after being invented six years4by Americans Dee Horton and Lew Hewitl. They5as a novelty feature, but as their use has grown, their 6 have extended within our technologically advanced world.Particularly7in busy locations or during times of emergency, the doors8crowdmanagement by reducing the obstacles put in people's way.9 making access both in and out of buildings easier for people, the difference in the way many of these doors open helps reduce the total area10 by them. Automatic doors often open to the side, with the panels sliding across one another. Replacing swing doors, these 11 smaller buildings to maximise the usable space inside without having to12 the way for a large, sticking-out door. There are many different types of automatic door, with each13 specific signals to tell them when to open.14 these methods differ, the main15 remain the same.Each automatic door system 16 the light, sound weight or movement in their vicinity as a signal to open. Sensor types are chosen to 17 the different environments they are needed in.18,a busy street might not19 a motion-sensored door, as it would constantly be opening for passers-by. A pressure sensitive mat would be more20 to limit the surveyed area.1.[A]Through [B]Despite [C]Besides [D]Without2.[A]revealing [B]demanding [C]improving[D]tracing3.[A]experience [B]convenience[C]guidance [D]reference4.[A]previously[B]temporarily [C]successively [D]eventually5.[A]held on [B]started out[C]settled down [D]went by6.[A]relations [B]volumes [C]benefits[D]sources7.[A]useful[B]simple [C]flexible [D]stable8.[A]call for [B]yield to [C]insist on [D]act as9.[A]As well as[B]In terms of [C]Thanks to [D]Rather than10.[A]connected[B]shared [C]represented [D]occupied11.[A]allow[B]expect [C]require [D]direct12.[A]adopt [B]lead [C]clear[D]change13.[A]adapting te [B]deriving from [C]relying on[D]pointing at14.[A]Once [B]Since [C]Unless [D]Although15.[A]records [B]positions [C]principles[D]reasons16.[A]controls [B]analyses[C]produces [D]mixes17.[A]decorate [B]compare [C]protect [D]complement18.[A]In conclusion [B]By contrast [C]For example[D]Above all19.[A]identify [B]suit[C]secure [D]include20.[A]appropriate[B]obvious [C]impressive [D]delicateSection II Reading ComprehensionPart ADirections:Read the following four texts. Answer the questions below each text by choosing A,B,C or D. Mark your answers on the ANSWER SHEET.(40 points)Text 1Nearly 2000 years ago, as the Romans began to pull out of Scotland, they left behind a curious treasure:10 tons of nails, nearly a million of the things. The nail hoard was discovered in 1960 in a four-metre-deep pit covered by two metres of gravel.Why had the Romans bunied a million nails? The likely explanation is that the withdrawal was rushed, and they didn't want the local Caledonians getting their hands on 10 tons of weapon-grade iron. The Romans buried the nails so deep that they would not be discovered for almost two millennia.Later civilisations would value the skilled blacksmith's labour in a nail even more than the raw material. As Roma Agrawal explains in her new delightful book Nuts and Bolts, early 17th-century Virginians would sometimes bum down their homes if they were planning to relocate. This was an attempt to recover the valuable nails, which could be reused after sifting the ashes. The idea that one might bum down an entire house just to reclaim the nails underlines how scarce, costly and valuable the simple-seeming technology was.The price of nails fell by 90%between the late 1700s and mid-1900s,as economist Daniel Sichel points out in a research paper. According to Sichel, although the falling price of nails was driven partly by cheaper iron and cheaper energy, most of the credit goes to nail manufactures who simply found more efficient ways to turn steel into nails.Nails themselves have changed over the years, but Sichel studied them because they haven't changed much. Roman lamps and Roman chariots are very different from LED strips and sports cars,but Roman nails are still clearly nails. It would be absurd to try to track the changing price of sports cars since 1695,but to ask the same question of nails makes perfect sense.I make no apology for being obsessed by a particular feature of these objects: their price. I am an economist, after all. After writing two books about the history of inventions, one thing Ive leamt is that while it is the enchantingly sophisticated technologies that get all the hype, it's thecheap technologies that change the world.The Gutenberg printing press transformed civilisation not by changing the nature of writing but by changing its cost-and it would have achieved little without a parallel collapse in the price of surfaces to write on, thanks to an often-overlooked technology called paper. Solar panels had few niche uses until they became cheap; now they are transforming the global energy system.21.The Romans buried the nails probably for the sake of[A]saving them for future use[B]keeping them from rusting[C]letting them grow in value[D]hiding them from the locals22.The example of early 17th-century Virginians is used to[A]highlight the thriftiness of early American colonists[B]illustrate the high status of blacksmiths in that period[C]contrast the attitudes of different civilisations toward nails[D]show the preciousness of nail-making technology at that time23.What played the major role in lowering the price of nails after the late 1700s?[A]Increased productivity.[B]Wider use of new energies.[C]Fiercer market competition.[D]Reduced cost of raw materials.24.It can be leamed from Paragraph 5 that nails[A]have undergone many technological improvements[B]have remained basically the same since Roman times[C]are less studied than other everyday products[D]are one of the world's most significant inventions25.Which of the following best summarises the last two paragraphs?[A]Cheap technologies bring about revolutionary change.[B]Technological innovation is integral to economic success.[C]Technology defines people's understanding of the world.[D]Sophisticated technologies develop from small inventions.Text 2Parenting tips obtained from hunter-gatherers in Africa may be the key to bringing up more contented children, researchers have suggested. The idea is based on studies of communities such as the Kung of Botswana, where each child is cared for by many adults. Kung children as young as four will help to look after younger ones and baby-wearing", in which infants are carried in slings, is considered the norm.According to Dr Nikhil Chaudhary, an evolutionary anthropologist at Cambridge University, these practices, Known as all oparenting, could lead to less anxiety for children and parents.Dr Annie Swanepoel, a child psychiatrist, believes that there are ways to incorporate them into western life. In Germany, one scheme has paired an old people's home with a nursery. The residents help to look after the children, an arrangement akin to alloparenting. Another measure could be encouraging friendships between children indifferent school years to miror the unsupervised mixed-age playgroups in hunter-gatherer communities.In a paper published in the Journal of Child Psychology and Psychiatry, researchers said that the western nuclear family was a recent invention which family broke with evolutionary history. This abrupt shift to an "intensive mothering narrative", which suggests that mothers should manage childcare alone, was likely to have been harmful. "Such narratives can lead to maternal exhaustion and have dangerous consequences, "they wrote.By contrast, in hunter-gatherer societies adults other than the parents can provide almost half of a child's care. One previous study looked at the Efe people of the Democratic Republic of Congo. It found that infants had an average of 14 alloparents a day by the time they were 18 weeks old and were passed between caregivers eight times an hour.Chaudhary said that parents now had less childcare support from family and social networks than during most of humans'evolutionary history,but introducing additional caregivers could reduce stress and maternal depression,which could have a“knock-on"benefit to a child's wellbeing.An infant bom to a hunter-gatherer society could have more than ten caregivers-this contrasts starkly to nursery settings in the UK where regulations call for a ratio of one carer to four children aged two to three.While hunter-gatherer children leamt from observation and imitation in mixed-age playgroups,researchers said that western"instructive teaching",where pupils are asked to sit still,may contribute to conditions such as attention deficit hyperactivity disorder.Chaudhary said that Britain should explore the possibility that older siblings helping their parents“might also enhance their own social development”26.According to the first two paragraph,alloparenting refers to the practice of[A]sharing child care among community members[B]assigning babies to specific adult caregivers[C]teaching parenting details to older children[D]carrying infants around by their parent27.The scheme in Germany is mentioned to illustrate[A]an attempt to facilitate intergenerational communication[B]an approach to integrating alloparenting into western culture[C]the conventional parenting style in western culture[D]the differences between western African ways ofliving28.According to Paragraph 4,the"intensive mothering narrative"_[A]alleviate parenting pressure[B]considerate family relationships[C]results in the child-centered family[D]departs from the course of evolution29.According to paragraph 6,what can we lean about nursery in the UK?[A]They tend to fall short of official requirements.[B]They have difficulty finding enough caregivers.[C]They ought to improve their carer-to-child ratio.[D]They should try to prevent parental depression.30.Which of the following would be the best title?[A]Instructive teaching:a dilemma for anxious parents[B]For a happier family,learn from the hunter-gatherers[C]Mix-aged playgroup,a better choice for lonely children[D]Tracing the history of parenting:from Africa to EuropeText 3Rutkowski is a Polish digital artist who uses classical painting styles to create dreamy fantasy landscapes.He has made illustrations for games such as Sony's Horizon Forbidden West,Ubisoft's Anno,Dungeons&Dragons,and Magic:The Gathering.And he's become a sudden hit in the new world of text-to-image AI generation.His distinctive style is now one of the most commonly used prompts in the new open-source AI art generator Stable Diffusion,which was launched late last month.The tool,along with other popular image-generation AI models,allows anyone to create impressive images based on text prompts.For example,type in"Wizard with sword and a glowing orb of magic fire fights a fierce dragon GregRutkowski,"and the system will produce something that looks not a milion miles away from works in Rutkowski's style.But these open-source programs are built by scraping images from the Internet,often without permission and proper attribution to artists.As a result,they are raising tricky questions about ethics and copyright.And artists like Rutkowski have had enough.According to the website Lexica,which tracks over 10 million images and prompts generated by Stable Diffusion,Rutkowski's name has been used as a prompt around 93,000 times.Some of the world's most famous artists,such as Michelangelo,Pablo Picasso,and Leonardo da Vinci,brought up around 2,000 prompts each or less.Rutkowski's name also features as a prompt thousands of times in the Discord of another text-to-image generator,Midjourney.Rutkowski was initially surprised but thought it might be a good way to reach new audiences.Then he tried searching for his name to see if a piece he had worked on had been published.The online search brought back work that had his name attached to it but wasn't his.“It's been just a month.What about in a year?I probably won't be able to find my work out there because[the internet]will be flooded with AI art,"Rutkowski says."That's concerning."“There is a coalition growing within artist industries to figure out how to tackle or mitigate this,"says Ortiz.The group is in its early days of mobilization,which could involve pushing for new policies or regulation.One suggestion is that AI models could be trained on images in the public domain,and AI companies could forge partnerships with museums and artists,Ortiz says.31.What can be leamed about Rutkowski from the first two paragraphs?[A]He is enthusiastic about AI generation painting.[B]He is popular with the users of an Al art generator.[C]He attracts admiration from other illustrators.[D]He specializes in classical painting digitalization.32.The problem with open-source AI art generators is that they[A]lack flexibility in responding to prompts[B]produce artworks in unpredictable styles[C]make unauthorized use of online images[D]collect user information without consent33.After searching online,Rutkowski found[A]a unique way to reach audiences[B]a new method to identify Al images[C]AI-generated work bearing his name[D]heated disputes regarding his copyright34.According to Ortiz,AI companies are advised to[A]campaign for new policies or regulations[B]offer their services to public institutions[C]strengthen their relationships with AI users[D]adopt a different strategy for Al model training35.What is the text mainly about?[A]Artists'responses to Al art generation.[B]AI's expanded role in artistic creation.[C]Privacy issues in the application of Al.[D]Opposing views on AI development.Text 4The miracle of the Chesapeake Bay lies not in its depths,but in the complexity of its natural construction,the interaction of fresh and saline water and the mix of land and water.The shallows provide homes for hundreds of species while storing floodwaters,filtering pollutants from water,and protecting nearby communities from potentially destructive storm surges.All this was put at great risk late last month,when the US Supreme Court issued a ruling in an Idaho case that provides the EPA far less authority to regulate wetlands and waterways.Specifically,a 5-4 majority decided that wetlands protected by the EPA under it Clean Water Act authority must have a“continuous surface connection”to bodies of water.This narrowing of the regulatory scope was a victory for builders,mining operators and other commercial interests often at odds with environmental rules.And it carries"significant repercussions for water quality and flood control throughout the US,"as Justice Brett Kavanaugh observed.In Maryland,the good news is that there are many state laws in place that provide wetlands protections.But that's a very shortsighted view,particularly when it comes to the Chesapeake Bay.The reality is that water and the pollutants that so often come with it,don't respect state boundaries.The Chesapeake draws from a 64000-square-mile watershed that extends to Virginia,Pennsylvania,New York,West Virginia,the District of Columbia and Delaware.Will thosejurisdictions extend the same protections now denied under Sackett V.EPA?Perhaps some,but all?That seems unlikely.It is too easy,and misleading,to see such court rulings as merely standing up for the rights of land owners when the consequences can be so dire for their neighbors.And it's reminder that they EPA's involvement in the Chesapeake Bay program has long been crucial as the means to transcend the influence of deep-pocketed special interests in neighboring states.Pennsylvania farmers,to use one telling example,aren't thinking about next year's blue crab harvest in Maryland when they decide whether to spread animal waste on their fields,yet the runoff into nearby creeks can have enormous impacts downstream.And so we would also call on state lawmakers from Richmond to Albany to consider reviewing their own wetlands protections and see for themselves the enormous stakes involved.We can't offer them a trip to the Chesapeake Bay model.It's been gone since the 1980s but perhaps a visit to Blackwater National Wildlife Refuge in Dorchester County where American bald eagles fly over tidal marshes so shallow you could not paddle a boat across them but teaming with aquatic life.It's worth the scenic drive.36.The Chesapeake Bay is described in Paragraph 1 as[A]a value natural environment[B]a controversial conservation area[C]a place with commercial potential[D]a headache for nearby communities37.The U.S.Supreme Court's ruling in the Idaho case[A]reinforces water pollution control[B]weakens the EPA's regulatory power[C]will end conflicts among local residents[D]may face opposition from mining operators38.How does the author feel about the future of the Chesapeake Bay?[A]Worried.[B]Puzzled.[C]Relieved[D]Encouraged.39.What can be inferred about the EPA's involvement in the Chesapeake BayProgram?[A]It has restored the balance among neighboring jurisdictions.[B]It has triggered a radical reform in commercial fisheries.[C]It has set a fine example of respecting state authorities.[D]It has ensured the coordination of protection efforts.40.The author holds that the state lawmakers should[A]be cautious about the influence of landowners[B]attach due importance to wetlands protections[C]recognize the need to expand wildlife refugesPart BDirections:Read the following comments on a report about American museums returning artifacts to their countries of origin and a list of statements summarizing the comments.Choose the best statement from the list A-G for each numbered name(41—45).There are two extra choices which you do not need to use.Mark your answers on the ANSWER SHEET.(10 points)(41)HannabSimply,there are people in Nigeria who cannot travel to the Smithsonian Institution to see that part of their history and culture represented by the Benin Bronzes.These should be available to them as part of their cultural heritage and history and as a source of national pride.There is no good reason that these artifacts should be beyond the ordinary reach of the educational objectives or inspiration of the generations to which they were left.They serve no purpose in a museum in the United States or elsewhere except as curious objects.They cannot be compared to works of art produced for sale which can be passed from hand to hand and place to place by purchase.(42)BuckWe know very exact reproductions of artwork can be and are regularly produced.Perhaps museums and governments might explore some role for the use of nearly exact reproductions as a means of resolving issues relating to returning works of art and antiquities.The context of any exhibit is more important to me than whether the object being displayed is 2,000 years old or 2 months old.In many cases the experts have a hard time agreeing on what is the real object and what is a forgery.Again,the story an exhibit is trying to tell is what matters.The monetary value of the objects on display is a distant second place in importance.(43)SaraWhen visiting the Baltimore Museum of Art,I came across a magnificentlSth-century Chinese sculpture.It inspired me to learm more about the culture that it represented.Artifacts in museums have the power to inspire,and perhaps spark that need to learn and understand the nature of their creators.Having said that,I do feel that whatever artifacts find their way to public museums should,in fact,be sanctioned as having been obtained on loan,legally purchased,or obtained by treaty.Stealing artifacts from other peoples'cultures is obscene;it robs not only the physical objects,but the dignity and spirit of their creators.(44)VictorAncient art that is displaced in foreign countries should be returned.…(缺失)(45)JuliaTo those of you in the comments section,by all means,who are having strong feeling about artifacts being removed from cities in the US and Britain,I would ask you to consider…(缺失)[A]It is clear that countries of origin have never been compensated for stolen artifacts.[B]It is a flawed line of reasoning to argue against returning artifacts to their countries of origin.[C]Museum visitor can still learn as much from artifacts copies after the originals are returmed.[D]Reproductions,even if perfectly made,cannot take the place of the authentic objects.[E]The real value of artifacts can only be recognized in their countries of origin rather than anywhere else[F]Ways to get artifacts from other countries must be decent and lawful.[G]Concern over security is no excuse for refusing to return artifacts to their countries of origin. 参考答案：41.E 42.C 43.F 44.G 45.BPart CDirections:Read the following text carefully and then translate the underlined segments into Chinese.Your translation should be written clearly on the ANSWER SHEET.(10 points)“Elephants never forget”—or so they say—and that piece of folklore seems to have some foundation.The African savanna elephant also known as the African bush elephant,is distributed across 37 African countries.(46)They sometimes travel more than sixty miles to find food or water,anc are very good at working out where other elephants are—even when they are out of ing tracking devices,researchers have shown that they have"remarkable spatial acuity",when finding their way to waterholes,they headed off in exactly the right direction,on one occasion from a distance of roughly thirty miles.What is more,they almost always seem to choose the nearest water hole.(47)The researchers are convinced that the elephants always know precisely where they are in relation to all the resources they need,and can therefore take shortcuts,as well as following familiar routes.Although the cues used by African elephants for long-distance navigation are not yet understood,smell may well play a part.Elephants are very choosy eaters,but until recently litle was known about how they selected their food.(48)One possibility was that they merely used their eyes and tried out the plants they found,but that would probably result in a lot of wasted time and energy,not least because their eyesight is actually not very good.(49)The volatile chemicals produced by plants can be carried a long way,and they are very characteristic:Each plant or tree has its own particular odor signature.What is more,they can be detected even when they are not actually visible.New research suggests that smell is a crucial factor in guiding elephants—and probably other herbivores—to the best food resources.The researchers first established what kinds of plant the elephants preferred either to eat or avoid when foraging freely.They then set up a“food station”experiment,in which they gave elephants a series of choices based only on smell.(50)The experiment showed that elephants may well use smell to identify patches of trees that are good to eat,and secondly to assess the quality ofthe trees within each patch.Free-ranging elephants presumably also use this information to locate their preferred food.参考译文：(46)它们有时跋涉六十多英里寻找食物或水，并且非常善于寻找其他大象的位置——即使它们不在视线范围内。
基于时间效应的广义信度模型
基于时间效应的广义信度模型刘志海;张强【摘要】Considering the target premium ,the credibility estimator with time effects under bal‐anced loss function was derived by means of credibility theory .The credibility factor depends on the time changeable effects .%考虑保费的目标估计，利用信度定价原理对具有时间效应的风险保费进行了研究，得到了平衡损失函数下的信度估计。
结果表明，信度因子依赖于时间变化效应。
【期刊名称】《山东理工大学学报（自然科学版）》【年(卷),期】2014(000)006【总页数】3页(P67-69)【关键词】平衡损失函数;时间效应;信度估计【作者】刘志海;张强【作者单位】哈密市商业银行股份有限公司，新疆哈密839000;石河子大学理学院，新疆石河子832000【正文语种】中文【中图分类】F840.69;O211在非寿险精算中,信度理论来对未来时期经验保费的厘定具有重要的意义.主要是通过结合投保人个人的索赔经历与先验保费来共同决定保费，所制定的保费为两者的加权和.关于信度理论的详细介绍，可见文献[1].为了计算各种情况下的信度保费，人们建立了各种各样的信度模型，多数假设历史时期的索赔具有共同的风险参数,在风险参数给定下,各期的索赔满足独立同分布的的条件.然而,在保险实务中，这种假设有时候是不成立的，风险参数对时间存在着依赖性.近年来，关于风险之间的相依性的研究受到越来越多的精算研究者的关注.文献[2]在提出一种共同效应随机变量的前提下，建立了风险间有某种相依结构的信度模型，文献[3]提出了共同效应相依的信度模型，推广了文献[2]的结果. 此外，文献[4]在风险不是独立的条件下，得到了风险等相关的多合同模型的估计.文献[5]考虑了给定风险参数历史索赔服从不同分布的情形，得到了风险间等相关下的广义信度估计.文献[6]在假设误差呈现等相关正态—正态分布下得到了Bayes保费，建立了误差等相关的Bühlmann信度模型，从而推广到Bühlmann-Straub信度情形.文献[7]研究了不同年风险间的时间效应，在平方损失函数下给出了具有时间变化效应的信度模型. 另一方面，保险公司制定下一年保费的时候，往往希望与某个目标(如上一年的保费等)相差较小.平衡损失函数得到了广泛的应用，文献[8]在平衡损失函数下讨论了广义的信度模型.文献[9]在平衡损失函数下给出了Bühlmann-Straub模型的信度估计，并讨论了性质.文献[10]在平衡损失函数下给出了风险具有共同效应的信度估计，推广了文献[9]的结果.文献[11]在平衡损失函数下研究了风险相依回归的信度模型，同时得到了风险等相关与共同效应的回归信度估计.本文考虑了不同年份的风险有时间效应，采用某种相关矩阵来刻画时间变化效应，在平衡损失函数下讨论了具有时间变化效应的信度估计.1 模型假设与准备知识本文研究满足如下假设的风险间具有时间变化效应的信度模型.假设1 时间变化效应用随机变量Θ表示, 给定Θi=θ,索赔Xi，i=1,2,…,n是相互独立的,且假设2 随机变量Θi的分布函数为πi(Θ)，有相同的均值E[μ(Θi)]=μ，但不同的方差和协方差Cov(μ(Θi),μ(Θj))=τiτj,j=1,2,…,n.假设3 平衡损失函数为如下形式L(A,B)=w(δO(X)-A-BX)2+(1-w)(Xn+1-A-BX)2(1)其中δO(X)为Xn+1的已知目标估计在上述的假定下，我们的目标是基于所有的历史索赔数据X=(X1,X2,…Xn)′，来估测未来年的索赔Xn+1的保费，此时需要解决最小化问题(2)样本函数类称为样本的非齐次函数类.通过解决问题(3)得到未来保费的非齐次信度估计，记作为统计δ0(X)，给出下列记号引入记号μδ=E[δ0(X)],Cov(δ0(X),Xi)=d,d=(d1,d2,…,dn)下面陈述一些准备型的引理.引理1 在假设1，假设2下，有以下结论(1)Xi的均值E(Xi)=γiμ,i=1,2,…,n(2)X可表示为X=(X1,X2,…,Xn)′,Cov(Xn+1,X)=τn+1(τ1,τ2,…,τn)详细证明可参见文献[3].引理2 设随机向量的数学期望和协方差矩阵分别为和则有使得E(Y-A-BX)(Y-A-BX)′在矩阵的非负定意义下达到最小解为其中∑YX是Y与X的协方差矩阵，证明可见文献[12].由引理2可知，随机变量Y在随机向量X的非齐次函数类L(X,1)上的正交投影为非齐次信度估计，即有(3)2 平衡损失函数下的信度保费估计定理1 在假设1和2下，通过求解最小化问题，可得未来索赔Xn+1的非齐次信度估计为其中：证明令Y=IδO(X)+(1-I)Xn+1,随机变量I满足P(I=1)=1-P(I=0)=w.此时最小化问题转化为(4)(5)由Y的定义，E(Y)可表示为E(Y)=wμδ+(1-w)μ(6)事实上有E(Y|I)=E(X),从而可知Cov(E(Y|I),E(X|I))=0协方差矩阵∑YX为∑YX=Cov(Y,X)=wCov(δ0(X),X)+ (1-w)Cov(Xn+1,X)=wd+(1-w)τn+1(τ1,τ2,…,τn)通过引理1，有(7)和(8)注1 若w=0，此时信度估计为此结果为平方损失函数下具有时间变化效应的信度估计，具体可见文献[3].定理1 的结论是其的推广.3 结束语信度理论作为非寿险精算学的核心内容之一，已成为非寿险保险公司精算部门重要的工具.由于现实复杂，一般情况下，风险之间都存在着某种相依性.本文考虑历年风险具有时间效应，在平衡损失函数下得到了风险具有时间变化效应的信度保费，所得到的信度估计依然为经典信度模型的加权形式，这一结果推广了经典的信度模型，可为非寿险保险公司制定下期保费提供理论依据.参考文献【相关文献】[1] 温利民,林霞,王静龙. 平衡损失函数下的信度模型[J].应用概率统计,2009,25(5):553-560.[2] 张强,崔倩倩,张娟.一类基于风险等相关的广义信度保费[J].山东理工大学：自然科学版,2012,26(6):98-102.[3] 郑丹,章溢,温利民.具有时间变化效应的信度模型[J].江西师范大学学报：自然科学版,2012,36(3):249-252.[4] Bühlmann H, Gisler A. A course in credibility theory and its application[M].Netherlands: Springer, 2005.[5] Yeo K L, Valdez E, Valdez E. A Claim Dependence with Common Effects in Credibility Models[J].Insurance: Mathematics and Economics, 2006, 38(3):609-629.[6] Wen L M, Wu X Y, Zhou X. The credibility premiums for models with dependence induced by common effects[J]. Insurance: Mathematics and Economics, 2009, 44(1):19-25.[7] Wen L M. The credibility models with equal correlation risks[J]. Journal of Systems Science and Complexity, 2011,24(3):532-539.[8] Wen L M，Wang W，Yu X L．Credibility models with error uniformdependence[J]．Journal of East China Normal University:Natural Science,2009,9(5)：119-126．[9] Gomez-Deniz E. A Generalization of the credibility theory obtained by using the weighted balanced loss function[J]. Insurance: Mathematical and Economics, 2008,42(2):850-854.[10] Hwang W Z, Wu X Y. The credibility premiums with common effects obtained under balanced loss functions[J]. Chinese Journal of Applied Probability andStatistics,2012,28(2):203-216.[11] Hwang W Z. Regression credibility model with correlation risk under balanced loss function[J]. Journal of East China Normal University :Natural Science, 2013(1):30-40. [12] Radhakrishna R C, Toutenburg H,Shalabh H C,et al.Linear models and generalizations:least squares and alternatives[M].New York:Springer,1995.。
国际航运市场(FFA)
Bcl、BPI和BSI指数的构成航线如下: 1.Bcl指数的构成航线及其权重: C2:图巴朗/鹿特丹16万长吨(10%误差)铁矿石运输航线，不包括装卸费， 包括节假日6天装卸，抵达装卸港后6小时起算，宣载时间在指数制作 日后10天内，销约时间在指数制作日后30天内，船龄最大18年，运价 按照每长吨计算，佣金率为3.75%，权重10%; c3:图巴朗/北仑、宝山15万吨(10%误差)铁矿石航线，不包括装卸费，18 米吃水，装载效率根据港口条件而定，卸载效率为3万吨每晴天工作 日，抵达装载港后6小时内起算，抵达卸载港后24小时内起算，宣载 时间在指数制作日后20天内，销约时间在指数制作日后35天内，船龄 最大18年，运价按照每公吨计算，佣金率3.75%，权重15%: c4:理查德湾/鹿特丹15万吨(10%误差)煤炭运输航线，报价不包括装卸平 舱费，装载效率根据港口条件，卸载效率2.5万吨每晴天工作日。装卸 时间从抵达装港后18小时内，抵达卸港后12小时内起算.宣载时间在指 数制作日后25禾内，销约时间在指数制作日后40天内，航线船龄最大 15年。运价按照每公吨计算，佣金率3.75%，权重5%: C5:西澳大利亚/北仑、宝山15万吨(10%误差)铁矿石运输航线，不包括装 卸费，18米吃水，装载效率根据港口规定，卸载效率3万吨每晴天工 作日。装卸时间从抵达装卸港后6小时内起算，抵达卸货港后24小时 内起算。宣载时间在指数制作日后20天内，销约时间在指数制作日后 35天内，船龄最大18年。运价按照每公吨计算，佣金率3.75%，权重 15%:
Hale Waihona Puke 表3 IMAREX－NOS上市交易及结算品种
干货 -------程租 标的物－航线 单个航线 211：C4，好望角型，理查德湾-鹿特丹， 150,000 mt 212：C7，好望角型，玻利维亚-鹿特丹， 150,000mt 213：C4 AVG：好望角型，理查德湾-鹿特丹， 150,000mt 214：C7 AVG：好望角型，玻利维亚-鹿特丹， 150,000mt -------期租 干货 241：P，巴拿马型，期租，直布罗陀-远东 242：P，巴拿马型，期租，韩国-日本(环太平洋航线) 一篮子航线 220： CS4TC， 好望角型， 期租平均 250： PM4TC， 巴拿马型， 期租平均 270： HS6TC， 灵便型， 期租平均 290： SM6TC， 超灵便型， 期租平均 单个航线 101： TD7， 阿芙拉型， 北海-欧洲大陆， 80,000mt 102： TD9， 阿芙拉型， 加勒比海-美湾， 70,000mt 103： TD5， 苏伊士型， 西非-美东， 130,000mt 104： TD3， VLCC， 海湾-日本， 260,000mt 106： TD12， 巴拿马型， 欧洲西北岸-美湾， 55,000mt 107： TD8， 阿芙拉型， 科威特-新加坡， 80,000mt 108： TD17，阿芙拉型，波罗的海-欧陆， 100,000mt 单个航线 151： TC4， MR型， 新加坡-日本， 30,000mt 152： TC2， MR型， 欧洲大陆-美东， 37,000mt 153： TC1， LR2型， 海湾-日本， 75,000mt 154： TC5， LR1型， 海湾-日本， 55,000mt 155： TC6， MR型， 阿尔及利亚-地中海， 30,000mt 发布单位 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 波罗的海交易所 普氏 波罗的海交易所 普氏 普氏 波罗的海交易所
海洋英文ppt介绍
Proposal for Marine Environmental Protection
"Protecting our Oceans
A Call to Action": This article outlines the urgent need for marine environmental protection, including measures to reduce pollution, preserve biodiversity, and mitigate climate change impacts on the ocean
The Voyage of the Beagle
This story accounts for the journal of Charles Darwin and the HMS Beagle around the world, including his observations and collections that led to his theory of evolution
The ocean is home to a diverse range of marine ecosystems, each supporting unique communities of plants and animals
Marine biodiversity includes phytoplankton, coral reefs, mollusks, fish, and marine mammals
"Marine Sanctuaries
Safe Havens for Ocean Life": This article endorses for the creation of marine sanctuaries, as where fishing and extractive activities are restricted in order to protect critical habitats and restore degraded ecosystems
巴以冲突英文ppt全文
Children as terrorists?
Propaganda is rife from both sides.
Are children really being used as terrorists?- or is this Israel trying to make the Palestinians look immoral?
Israel-cities.
The Jewish people have been very industrious. They have built up large modern cities with efficient infrastructures. At the same time they have not neglected their traditions however. They see these as major reasons why they have survived as a people.
The results-notice the bodies.
Another bus bomb- note the body.
US President George W.Bush. He is shown here as a puppeteercontrolling the Israeli prime Minister. The title shows the belief that Israel’s money comes from the USA.
Soldiers are even fearful of children. What has the child got
in the bags? Is he a terrorist?
资本资产定价模型与单因素模型
SML ： ri = rf + β[ E(rm) – rf ]
βi = [ Cov (ri,rm) ] / σm2
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投资分析 对外经济贸易大学
8
W1 W2 … WGE
… Wn
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协方差矩阵
W1
W2
…
Cov(r1,r1) Cov(r1,r2) …
2 m
E(Ri ) R f [E(Rm ) R f ]
即证券市场线
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投资分析 对外经济贸易大学
12
证券市场直线
E(r)
E(r)
CML
E(rM)
M
E(rM)
rf
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rf (r)
投资分析 对外经济贸易大学
SML
E(rM-rf)
M
=1
13
证券市场线的经济意义
在均衡状态，单个资产的边际风险带来的边际收 益等于风险的市场价格
有29.58％与市场组合的变化有关
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投资分析 对外经济贸易大学
31
波音公司的贝塔值
贝塔值
月收益率 0.94 周收益率 1.05 日收益率 0.37
标准差
0.21 0.27 0.26
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投资分析 对外经济贸易大学
R2
0.26 0.21 0.03
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阿尔法与贝塔战略---股票选择与市场时 机选择
E(rM) – rf M
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每单位风险溢价， 是市场组合的夏普比率，也是 风险的市场价格
投资分析 对外经济贸易大学
航运术语缩写大全
航运术语缩写大全(一）英文缩略语英文原文中文译文A·A·ALWAYS AFLOAT 永远漂浮ABT ABOUT 大约,关于A／C ACCOUNT 计算A／C ACCOUNT CURRENT 账户ACCT ACCOUNT 账目，账户ACCDLY ACCORDINGLY 因此，相应的A·&C·P·ANCHORS&CHAINS 锚和锚链试验台ACPT ACCEPTANCE 接受ADCOM ADDRESS COMMISSION 订舱佣金，租船佣金M ADDRESS COMMISSION 订舱佣金，租船佣金ADFT AFT DRAFT 艉吃水ADV. ADVISE 通知ADV ADVANCE 提前A·F· ADVANCED FREIGHT 预付运费A·F·B·AIR FREIGHT BILL 空运运单AFMT AFTER FIXING MAIN TERMS 主要(租船)条款确认以后AGRD AGREED 同意 AGRT AGREEMENT 协议AGT AGENT 代理AGW ALL GOING WELL 取决于）一切顺利A·H·AFTER HATCH 后舱AM MORNING 上午A·M· ABOVE MENTIONED 上述的AMT AMOUNT 金额、数额A·N · ARRIVAL NOTICE 到达通知A／P ADDITIONA PRIMIUM 额外保险费\\老船加保费APPR APPROXIMATE 大约APPROX APPROXIMATE 大约A/R ALL RlSKS AGAINST ALL 一切险、承保一切风险A/S AFTER SIGHT 见票后A/S AFTER ALONGSIDE 船边ASAP AS S00N AS POSSIBLE 尽，决、尽速ASF AS FOLLOWS 如下ASST ASSISTANT 助理，援助ATL ACTUAL TOTAL LOSS 实际全损ATTN ATTENTION 由··收阅AUTO AUTOMATIC 自动的A.V AD VALOREM 从价费率AVG AVERAGE 平均,海损BA BALE CAPACITY 包装容积BAF BUNKER ADJUSTMENT FACTOR 燃油附加费BAL BALANCE 平衡、余额、差额BUTC BALTIME UNIFORM TIME CHARTER 统一定期租船合同，“波尔的摩"期祖合同 BB BELOW BRIDGES 桥楼以下（容积)BD BANKING DAYS 银行工作日B／D BAR DRAUGHT 河口）沙洲吃水BDI BOTH DATES INCLUSIVE 包括首尾两日BDL BUNDLE 捆B/E BILL OF EXCHANGE／BILL OF ENTRY 汇票／进口报告书BEAM BREADTH OF THE VESSEL 船宽BENDS BOTH ENDS 装卸港BFI BALTIC FREIGHT INDEX 波罗的海运价指数B／G BONDED GOODS 保税货物BG BAGS 袋B／H BILL OF HEALTH 健康证明书BIMCO BALTIC INTERNATIONAL MARITIME CONFERENCE波罗的海国际航运公会BIZ BUSINESS 业务B／L BILL OF LADING 提单BL BLADING BILL OF LADING 提单BLFT BALE FEET 包装尺码（容积）BLK BULK 散装BLKR BULKER 散装船BLT BUILT （船舶）建造(年月)BM BEAM 横梁(船舶型宽）B。
tpo40三篇托福阅读TOEFL原文译文题目答案译文背景知识
tpo40三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (5)题目 (8)答案 (17)背景知识 (17)阅读-2 (20)原文 (20)译文 (23)题目 (25)答案 (35)背景知识 (35)阅读-3 (38)原文 (38)译文 (41)题目 (44)答案 (53)背景知识 (54)阅读-1原文Ancient Athens①One of the most important changes in Greece during the period from 800 B.C. to 500 B.C. was the rise of the polis, or city-state, and each polis developed a system of government that was appropriate to its circumstances. The problems that were faced and solved in Athens were the sharing of political power between the established aristocracy and the emerging other classes, and the adjustment of aristocratic ways of life to the ways of life of the new polis. It was the harmonious blending of all of these elements that was to produce the classical culture of Athens.②Entering the polis age, Athens had the traditional institutions of other Greek protodemocratic states: an assembly of adult males, an aristocratic council, and annually elected officials. Within this traditional framework the Athenians, between 600 B.C. and 450 B.C., evolved what Greeks regarded as a fully fledged democratic constitution, though the right to vote was given to fewer groups of people than is seen in modern times.③The first steps toward change were taken by Solon in 594 B.C., when he broke the aristocracy's stranglehold on elected offices by establishing wealth rather than birth as the basis of office holding, abolishing the economic obligations of ordinary Athenians to the aristocracy, and allowing the assembly (of which all citizens were equal members) to overrule the decisions of local courts in certain cases. The strength of the Athenian aristocracy was further weakened during the rest of the century by the rise of a type of government known as a tyranny, which is a form of interim rule by a popular strongman (not rule by a ruthless dictator as the modern use of the term suggests to us). The Peisistratids, as the succession of tyrants were called (after the founder of the dynasty, Peisistratos), strengthened Athenian central administration at the expense of the aristocracy by appointing judges throughout the region, producing Athens’ first national coinage, and adding and embellishing festivals that tended to focus attention on Athens rather than on local villages of the surrounding region. By the end of the century, the time was ripe for more change: the tyrants were driven out, and in 508 B.C. a new reformer, Cleisthenes, gave final form to the developments reducing aristocratic control already under way.④Cleisthenes' principal contribution to the creation of democracy at Athens was to complete the long process of weakening family and clanstructures, especially among the aristocrats, and to set in their place locality-based corporations called demes, which became the point of entry for all civic and most religious life in Athens. Out of the demes were created 10 artificial tribes of roughly equal population. From the demes, by either election or selection, came 500 members of a new council, 6,000 jurors for the courts, 10 generals, and hundreds of commissioners. The assembly was sovereign in all matters but in practice delegated its power to subordinate bodies such as the council, which prepared the agenda for the meetings of the assembly, and courts, which took care of most judicial matters. Various committees acted as an executive branch, implementing policies of the assembly and supervising, for instance, the food and water supplies and public buildings. This wide-scale participation by the citizenry in the government distinguished the democratic form of the Athenian polis from other less liberal forms.⑤The effect of Cleisthenes’ reforms was to establish the superiority of the Athenian community as a whole over local institutions without destroying them. National politics rather than local or deme politics became the focal point. At the same time, entry into national politics began at the deme level and gave local loyalty a new focus: Athens itself. Over the next two centuries the implications of Cleisthenes’ reforms were fully exploited.⑥During the fifth century B.C. the council of 500 was extremely influential in shaping policy. In the next century, however, it was the mature assembly that took on decision-making responsibility. By any measure other than that of the aristocrats, who had been upstaged by the supposedly inferior "people", the Athenian democracy was a stunning success. Never before, or since, have so many people been involved in the serious business of self-governance. It was precisely this opportunity to participate in public life that provided a stimulus for the brilliant unfolding of classical Greek culture.译文古雅典①在公元前800年到公元前500年期间，希腊最重要的变化之一是城邦的崛起，并且每个城邦都发展了适合其情况的政府体系。
卡特（Cat）M314轮式挖掘机商品说明书
Cat® M314 Wheeled ExcavatorHigh Performance with Lower Fuel Consumption• Get the same productivity and results using up to 5 percent less fuel and work longer with a larger fuel tank over the M314F.• The Cat® engine matches your performance and production needs. The engine meets U.S. EPA Tier 4 Final, EU Stage V, and Korea Tier 4 Final emission standards.• Travel between sites is easier with travel speeds up to 37 km/h (22 mph).• From dirt to asphalt, the excavator matches your needs to get the job done in a timely, efficient manner.• The advanced hydraulic system provides the optimum balanceof power and efficiency while giving you the control you need for precise working requirements.• With up to 15 percent more swing torque, you can get the job done faster to move on to the next one.• The dedicated swing pump provides consistent power for better multi-tasking capabilities.• Auxiliary hydraulic options give you the versatility to use a wide range of Cat attachments.• Don’t let the temperature stop you from working. The excavator has a standard high-ambient temperature capability of 52° C (125° F) and cold start capability of –18° C (0° F).• Standard Product Link™ provides location, machine hours, fuel usage, productivity, idle time, diagnostic codes, and other machine data on demand through the VisionLink online interface, helping you improve job site efficiency and lowering operating costs.Work in Comfort• Choose between Deluxe and Premium cab options.• The Deluxe seat is heated and air adjustable while the Premium seat is heated, cooled and adjusts automatically.• Get in and out of the cab easier using the tip-up left console.• Feel more comfortable in the cab while you work with reduced cab vibrations from advanced viscous mounts.• Bluetooth® integrated radio allows for seamless mobile phone connection to listen to music, podcasts and hands-free calling.• Easily adjust to your ideal temperature with the touchscreen monitor or jog dial.• Control the excavator comfortably with easy-to-reach controls.• Stow your gear with plenty of in-cab storage beneath and behind the seat, overhead, and in the consoles. A cup holder, bottle holder, and coat hook are also provided.The Cat® M314 Wheeled Excavator offers easy-to-use controls, tilt rotator integration, a comfortable cab, and increased fuel economy. Save up to 10 percent in maintenance parts along with longer service intervals and 100 percent daily ground level maintenance to save you time and money. Not all features are available in all regions. Consult your Cat dealer for specific configurations available in your region.Cat® M314 Wheeled ExcavatorLower Maintenance Costs• Quickly check and service your machine with daily maintenance points accessible from ground level.• Check the engine oil level quickly and safely from the ground.• Save up to 10 percent in maintenance parts with the new, longer lasting filters.• Track your machine’s filter life and maintenance intervals on thein-cab monitor.• Two levels of fuel filtration protect the engine from dirty diesel.• The new hydraulic oil filter provides improved filtration performance, and longer life with a 3,000-hour replacement interval – 50 percent longer than previous filter designs.• S·O·S SM ports are located at ground level, simplifying maintenance and allowing for quick, easy extraction of fluid samples for analysis.• Keep costs down by sharing attachments with the 313 excavator.Simple to Operate• Start the engine with push-to-start button, a Bluetooth® key fob, smartphone app, or the unique Operator ID function.• Program your power mode and joystick preferences using Operator ID; the excavator remembers your settings each time you go to work.• Navigate quickly on the standard high-resolution 254 mm (10 in) touchscreen monitor or with the aid of the jog dial control.• Not sure how a function works or how to maintain the excavator? Simply access the operator’s manual on the touchscreen monitor.• The auto axle lock presses the pedal for you to reduce your overall number of actions. The machine automatically detects when the service brake and axle need to be locked or unlocked. It releases automatically when you press the travel pedal.Safety• Access daily maintenance points from ground level.• Keep your excavator secure with Operator ID. Use your PIN code on the monitor to enable the push button starting feature.• The standard ROPS cab meets ISO 12117-2:2008 requirements.• Enjoy better visibility into trenches, in each swing direction, and behind you with the help of smaller cab pillars, larger windows, and a flat engine hood design. Rearview and sideview cameras are standard along with optional 360 degree visibility system. • The service platform design provides easy, safe, and quick access to upper service platform; the service platform steps use anti-skid punch plate to prevent slipping.• The standard hydraulic lockout lever isolates all hydraulic and travel functions in the lowered position.• Ground-level shut-off switch stops all fuel to the engine when activated and shuts down the machine.2Cat® M314 Wheeled Excavator Standard and Optional EquipmentStandard and optional equipment may vary. Consult your Cat dealer for details.Combined flow/high-pressureauxiliary circuit✓Quick coupler circuit✓Wide Angle Mirrors✓Ground-level engine shutoff switch✓Handrail and hand holds on serviceplatform✓Signaling/warning horn✓3Cat® M314 Wheeled ExcavatorEngine Model Cat C4.4 Engine Power (ISO 14396)110 kW148 hp Bore105 mm 4 in Stoke127 mm 5 in Displacement 4.4 L268.5 in3• T he C4.4 meets Tier 4 Final, Stage V, and Korea Tier 4 Final emissionstandards.• N o engine power derating required below 3,000 m (9,843 ft) altitude.• E ngine power advertised is the power available at the flywheel when the engine is equipped with fan, air cleaner, exhaust gas aftertreatment, and alternator.• R ating at 2,000 rpmMain System – Maximum Flow Implement270 L/min71 gal/min Maximum Pressure – Equipment35 000 kPa5,076 psi Maximum Pressure – Travel35 000 kPa5,075 psi Maximum Pressure – Swing35 500 kPa5,149 psiSwing Speed9.1 rpm Maximum Swing Torque39 kN·m28,860 lb-ftOperating Weight Minimum15 000 kg33,069 lb Operating Weight Maximum18 000 kg39,683 lb • T ypical configurations include medium stick, 3100 kg (6,834 lb) counterweight, full fuel tank, operator, quick coupler (210 kg/463 lb), bucket (500 kg/1,102 lb) and dual pneumatic tires.Fuel Tank295 L77.9 gal Cooling System24 L 6.3 gal Engine Oil11 L 2.9 gal Diesel Exhaust Fluid (DEF)20 L 5.3 gal Final Drive 2.4 L0.6 gal Hydraulic System (including tank)220 L58.1 gal Hydraulic Tank90 L23.8 gal Boom 5 m (16'6")Stick 2.2 m (7'3") Bucket0.76 m3 (0.99 yd3) GD Shipping Height (top of cab)3315 mm10'11" Shipping Length8210 mm26'11" Tail Swing Radius2150 mm7'1" Counterweight Clearance1260 mm4'2" Ground Clearance335 mm1'1" Undercarriage Length4920 mm16'2" Wheel Base2500 mm8'2"Boom Type VA BoomStick R2.2CB (7'3") Bucket0.76 m3 (0.99 yd3) GD Dump Height7010 mm23' Digging Height5290 mm17'4" Reach at Ground Level8650 mm28'5" Vertical Wall Digging Depth4250 mm13'11"• R ange values are calculated with a tip radius of 1387 mm (4'6"). CW-typebucket (358-8665, GD, 1000 mm/3'3", 0.6 m³/0.73 yd³, with Advansys 70 tips) and CW-20S-D.4.N quick coupler. Breakout force values are calculated with a tip radius of 1224 mm (4'0") and heavy lift on. Pin-On Bucket (358-8619, GD, 1100 mm/3'7", 0.68 m³/0.89 yd³ with Advansys 70 tips) with no quick coupler.• T he air conditioning system on this machine contains the fluorinated greenhouse gas refrigerant R134a (Global Warming Potential = 1430). The system contains 0.85 kg of refrigerant which has a CO2 equivalentof 1.216 metric tonnes.Technical SpecificationsFor more complete information on Cat products, dealer services, and industry solutions, visit us on the web at © 2020 CaterpillarAll rights reservedMaterials and specifications are subject to change without notice. Featured machines in photos may include additional equipment. See your Cat dealer for available options.CAT, CATERPILLAR, LET’S DO THE WORK, their respective logos, “Caterpillar Yellow,” the “Power Edge” and Cat “Modern Hex”trade dress as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission. VisionLink is a trademark of Trimble Navigation Limited, registered in the United States and in other countries.AEXQ2741 (02-2020) Build Number: 07A(ANZ, Eur, N Am)。
西班牙的英语作文
Spain,a country rich in history,culture,and natural beauty,is a popular destination for travelers from around the world.Here is a brief essay on Spain,highlighting its key aspects:Geography and ClimateSpain is located in southwestern Europe,occupying most of the Iberian Peninsula.It is bordered by Portugal to the west,France and Andorra to the north,and the Mediterranean Sea to the east.The country boasts a diverse geography,from the Pyrenees mountain range in the north to the rolling hills of La Mancha in the center,and the arid plains of Andalusia in the south.The climate varies from Mediterranean along the coasts to alpine in the higher elevations and semiarid in the central plateau.History and CultureThe history of Spain is as rich as its landscapes.From the ancient Iberians and Celts to the Romans,Visigoths,Moors,and finally the Reconquista,Spains past is a tapestry of civilizations.This history is evident in the architectural marvels that dot the landscape, such as the Alhambra in Granada,the Sagrada Familia in Barcelona,and the Alcázar in Seville.Spanish culture is a blend of these influences,with a strong emphasis on art, music,and dance,particularly flamenco.Language and LiteratureSpanish,or Castilian,is the official language of Spain and is spoken by the majority of its population.It is the second most spoken language in the world by the number of native speakers.The country has produced some of the most renowned literary figures, including Miguel de Cervantes,author of Don Quixote,and Federico García Lorca,a leading figure in the Generation of27.CuisineSpanish cuisine is as diverse as its regions,with each area offering its own specialties. Tapas,small dishes served with drinks,are a cultural institution and a great way to experience a variety of flavors.Paella,a rice dish from Valencia,and churros,deepfried dough sticks,are also famous Spanish dishes.The country is also renowned for its wines, particularly Rioja and Cava.Festivals and TraditionsSpain is known for its vibrant festivals and traditions.Perhaps the most famous is the Running of the Bulls in Pamplona,which takes place every July.Other notable festivals include La Tomatina,where participants throw tomatoes at each other,and Semana Santa, when elaborate processions fill the streets during Holy Week.Economy and TourismSpain has a mixed economy,with strong sectors in tourism,agriculture,and industry.It is the worlds secondlargest producer of wine and a leading producer of olive oil.Tourism is a vital part of the economy,with millions visiting each year to enjoy its beaches,historic sites,and cultural attractions.In conclusion,Spain is a country that offers a unique blend of natural beauty,historical depth,and cultural richness.Whether you are interested in art,history,cuisine,or simply enjoying the sun and sea,Spain has something for everyone.。
投资学(双语)_课程大纲
《投资学（双语）》教学大纲课程编号：091333B课程类型：□通识教育必修课□通识教育选修课□专业必修课□√专业选修课□学科基础课总学时：48 讲课学时：48 实验（上机）学时：学分：3适用对象：资产评估先修课程：金融学1.教学目标（黑体，小四号字）投资学是随着我国金融市场的发展特别是资本证券市场的发展，高校为适应社会对从事金融证券投资业务活动的应用性专业人才不断扩大的需要而开设的一门课程。
本课程的教学目标是通过课堂教学，让学生系统地掌握投资领域的基本理论、熟悉金融工具的基本定价规律，在教学中立足开拓学生的国际视野，注重培养学生分析问题、解决问题的能力，为成为卓越评估师打下坚实的知识基础。
目标1：系统了解现代投资理论、原理和内在机制目标2：掌握各种金融工具的特点和定价规律。
目标3：在学习中注重培养学生分析问题、解决问题的能力。
2.教学内容及其与毕业要求的对应关系（黑体，小四号字）可包括但不限于：1.教学内容讲授上的要求精讲内容包括金融市场、基金、风险与收益、马克维茨投资组合理论、因素模型；粗讲投资过程、各种金融工具的特点。
2.教学方法、教学手段根据本课程的特点以及培养目标的要求，在教学中应遵循循序渐进、深入浅出的原则和理论与实践相结合的原则。
在课堂教学中以导读与释疑为主，教师以教学大纲为依据，以主要教材为蓝本，提要基本内容、识记基本概念、讲解基本原理、讲解重点难点，课下要求学生阅读大量投资领域相关文献以加深对课程所授知识的理解深度。
3.对课后作业以及学生自学的要求本课程在学习中将安排4-5次课外综合作业，重点考察学生所学知识的掌握程度。
对于一些容易理解的知识点放置课下学习，为学生提供探索与思考的空间。
4.该课程从哪些方面促进了毕业要求的实现（1）本课程学习可以帮助学生金融市场的运行规律，能够采用科学的方法从金融市场中搜集相关数据与信息并进行和分析处理，进而形成恰当投资决策；（2）本课程学习可以帮助学生逐渐形成团队协作意识，并在资产评估团队活动中发挥个人能力，同时与其他成员进行协调合作；（3）本课程学习可以帮助学生养成自主学习和终身学习意识，培养其创业创新能力及不断学习与适应发展的能力。
FRM一级模拟题(1)
FRM一级模拟题（1）1、The price of INDO stock on any trading day can either increase or decrease. A risk analyst estimates that there is a 20% probability that the price of INDO stock will increase on any trading day. This probability is assumed to be the same for all trading days and the price changes on any given trading day are independent of changes on other days. Based on this information, what is the expected number of days the share price will decrease in the coming five days?A. 3B. 5C. 4D. 12. Which one of the foll owing four statements about hypothesis testing holds true if the level of significance decreases from 5% to 1%?A.It becomes more difficult to reject a null hypothesis when it is actually true.B.The probability of making a type I error increases.C.The probability of making a type II error decreases.D.The failure to reject the null hypothesis when it is actually false decreases to 1%.3. Assume that a rand om variable foll ows a normal distribution with a mean of 100 and a standard d eviation of17.5. What is the probability that this rand om variable value is between 82.5 and 135?A.68%B.81.9%C.82.8%D.95%4. In country X, the probability that a letter sent through the postal system reaches its destination is 2/3. Assume that each postal delivery is independent of every other postal delivery, and assume that if a wife receives a letter from her husband, she will certainly mail a response to her husband. Suppose a man in country X mails a letter to his wife (also in country X) through the postal system. If the man d oes not receive a response letter from his wife, what is the probability that his wife received his letter?A.1/3B.3/5C.2/3D.2/55. Let X and Y are two rand om variables representing the annual returns of two different portfolios. If E[X ] = 3, E[Y ] = 4, and E[XY ] = 11, then what is Cov[X, Y ]?A.-1B.0C.11D.126. Kelly Lewis is analyzing daily return data for a stock market ind ex. From the available data, she calculates that the average daily return is 0.0% and the standard deviation is 1.5%. Concerned that a normal distribution likely underestimates tail risk, she recalls from extreme value theory that a generalized Pareto distribution (GPD) can be used to approximate the probability that the daily return is greater than a loss level y, given the daily return is a loss. That is, if X represents the daily return, then:Using maximum likelihood estimation with the available historical data, she finds that parameter values of? = 0.005 and? = 0.015 provid e the best fit. Given the daily return is a loss, what is the probability that the daily return exceeds –4.5% using a normal distribution and a generalized Pareto distribution?ing a normal distribution: 99.74%; using a generalized Pareto distribution: 94.91%ing a normal distribution: 99.87%; using a generalized Pareto distribution: 94.91%ing a normal distribution: 99.74%; using a generalized Pareto distribution: 97.45%ing a normal distribution: 99.87%; using a generalized Pareto distribution: 94.45%7. Rational Investment Inc. is estimating a daily VaR for its fixed-income portfolio currently valued at $800 million. Using returns for the past 400 days (ord ered in decreasing order, from highest daily return to lowest daily return), the daily returns are the foll owing: 1.99%, 1.89%, 1.88%, 1.87%, . . . , –1.76%, –1.82%, –1.84%, –1.87%, –1.91%.At the 99% confidence l evel, estimate the daily d ollar VaR using the historical simulation method.A.$14.08mmB.$14.56mmC.$14.72mmD.$15.04mm8. Assume that the P/L distribution of a liquid asset is i.i.d. normally distributed. The position has a one-day VaRat the 95% confidence level of $100,000. Estimate the 10-day VaR of the same position at the 99% confid ence level.A.$1,000,000B.$450,000C.$320,000D.$220,0009. On March 13, 2008, William Tell, a fund manager for the Rossini fund, takes a short position in the March Treasury bond (T-bond) futures contract. He plans to deliver the cheapest-to-d eliver Treasury bond with a coupon of 41/2 percent payable semiannually on May 15 and November 15, a conversion factor of 1.3256, and a face value of USD 100,000. The delivery date is Friday, March 15. The settl ement price for the cheapest-to-deliver Treasury bond on March 13 is 682/32. Calculate the invoice price.A.$90,118.87B.$91,727.79C.$92,367.75D.$95,619.4710. A newly issued noncallable fixed-rate bond with 30-year maturity carries a coupon rate of 5.5% and trades at par. Its duration is 13.84 years and its convexity is 529.714. Which of the foll owing statements about this bond is true?A.If the bond were to start trading at a premium, its duration woul d decrease.B.If the bond were to start trading at a discount, its duration would not change.C.If the bond were to remain at par, its duration woul d increase as the bond aged.D.If the bond were to remain at par, its duration woul d increase as the bond aged.Answer and Explanation:1、Prob (price up) = 0.20, meaning that Prob (price d own) = 0.80. It is the same for all days. Price change in a given day is independ ent of the price change on other days. So, the number of days where the stock price goes d own within 5 trading days has a binomial distribution with parameter n = 5 and q = 1 –0.20 = 0.80. Its expected value is 5(0.80) = 4.2、Type I error: The rejection of the null hypothesis when it is actually true. Type II error: The failure to reject the null hypothesis when it is actually false.The significance level is the probability of making a type I error.3、(A) is incorrect. Almost 68% of the observations will be within the interval from one standard deviation below the mean to one standard d eviation above the mean, which is within the interval [100 –17.5; 100 +17.5].(B) is correct. 82.5 =100–17.5 and 135 = 100 + 2*17.5. So, the percentage is 34% on the left-hand side of the mean, plus 95%/2 on the right-hand side of the mean.(C) is incorrect. Almost 95% of the items will lie within the interval from two standard deviations bel ow the mean to two standard deviations above the mean, that is, within the interval [100 – 2 * 17.5; 100 + 2 * 17.5]. (D) is incorrect. This answer assumes wrongly that 97.5% of the observations will be within [100 – 2 * 17.5; 100 + 2 * 17.5].4、A = Event that the wife receives the man's letterB = Event that the man d oes not receive a response from his wifeWe need to find P(A|B).First, we know P(A) = 2/3.To get P(B), note that there are three possible scenarios.(1). His letter d oes not get to his wife—probability is 1/3.(2). Her response letter does not get to him—2/9 (= 2/3 * 1/3, probability that she gets his letter times the probability that her letter gets lost).(3). Her response letter d oes get to him—4/9 (= 2/3 * 2/3, probability that she gets his letter times the probability that her letter gets to him).He does not receive a response in scenarios 1 and 2, so P(B) = 5/9.Next, we also know P(B|A) = 1/3 (if she receives the l etter, she responds, so he d oes not get a response only if the letter is l ost, which happens with probability 1/3).Then, by Bayes' rule, P(A|B) = P(B|A) * P(A) / P(B) = (1/3) * (2/3) / (5/9) = 2/5.5、We can rewrite Cov[X, Y ] as E[XY ] – E[X ]E[Y ]. Then, Cov[X, Y ] = 11 – 3 * 4 = –1.(A) is correct because the formula was used correctly, E[XY ] – E[X ]E[Y ].(B) is incorrect because it assumes zero covariance, which is false when the formula is used.(C) is incorrect because the product of the two expectations of X and Y was not subtracted from the joint expectation E[XY ].(D) is incorrect because the covariance is not the product of the two expectations of X and Y.6、The GPD value is derived simply by plugging in y = –0.045 in the equation. The normal distribution value is derived by:Prob(X > –0.045 | X < 0) = 1 – Prob(X < –0.045|X < 0)= 1 – (Prob(X < 0|X < –0.045) * Prob(X < –0.045)) / Prob(X < 0)= 1 – (1.0 * Prob(X < –0.045)) / Prob(X < 0)= 1 – Prob(Z < –3) / Prob(Z < 0)= 1 – 0.0013/0.5= 0.99747、VaR = 1.82% * 800 = 14.56 million Topic:VaR, nonparametric calculation8、The question tests the ability to convert VaRs. The one-day VaR should be multiplied by the square root of time and the ratio of the confidence intervals to get the correct VaR.Alternative (A) simply multiplies the VaR by T.Alternative (C) multiplies the VaR by the square root of T.Alternative (D) multiplies by the square root of T but inverts the ratio (1.64/2.32) instead of (2.32/1.64).9、The invoice is based on a settlement price of 682/32 or 68.0625. The accrued interest is cal culated on the basis of the number of days since the last coupon payment date, November 15, and the delivery date, March 15. That is 121. During the current six-month period between coupon payment dates, November 15 to May 15, there are 182 days. Thus the accrued interest on $100,000 face value of the bond is:121/182 * $100,000 * 0.045/2 = $1,495.88The invoice price is:$100,000 * 0.680625 * 1.3256 + $1,495.88 = $91,719.5310、(A) is correct. At higher interest rates, the bond/price relationship is cl oser to linear than it is when rates are l ow. So, the new duration woul d be lower than 13.84. Alternatively, one can think of duration as a weighted average of the times when cash fl ows are made, where the weights are the percentage of the total value of the bond. When rates rise, the present values associated with the later payments are relatively smaller and the duration falls.(B) is incorrect because it is the exact opposite of (A), the correct answer.(C) is incorrect. It fails to recognize the logic stated in (A).(D) is incorrect because duration is a function of the bond's maturity and, all else constant, duration woul d decrease as the bond's maturity shortened.参与FRM的考生可按照复习计划有效进行，另外高顿网校官网考试辅导高清课程已经开通，还可索取FRM 考试通关宝典，针对性地讲解、训练、答疑、模考，对学习过程进行全程跟踪、分析、指导，可以帮助考生全面提升备考效果。
CFA-LEVEL-I-数量总结
1. Over the past 240 months, an investor’s portfolio had a mean monthly return of 0.79%, with a standard deviation of monthly returns of 1.16%. According to Chebyshev’s inequality, the minimum number of the 240 monthly returns that fall into the range of −0.95% to 2.53% is closest to:
3. A portfolio manager annually outperforms her benchmark 60% of the time. Assuming independent annual trials, what is the probability that she will outperform her benchmark four or more times over the next five years?
survive 12 months, is 0.85:P(pass test | survivor) = 0.85. A. What is P(pass test | nonsurvivor)? B. Using Bayes’ formula, calculate the probability that a company is a survivor, given that
Portfolio 1 2 3
Expected return
22%
Standard deviation
40%
Roy’s Safety-First value 0.35 0.64
2025年人教版高考英语试题与参考答案
2025年人教版英语高考复习试题与参考答案一、听力第一节（本大题有5小题，每小题1.5分，共7.5分）1、What is the relationship between the two speakers?A) Teacher and studentB) Doctor and patientC) Shop assistant and customerD) Manager and employeeAnswer: C) Shop assistant and customerExplanation: In the conversation, one speaker asks about the size and color options available for a particular item of clothing, indicating that they are shopping. The other speaker responds with details about the stock and offers assistance, which is char acteristic of a shop assistant’s role.2、Where does the conversation most likely take place?A) At a hospitalB) In a classroomC) At a clothing storeD) In an officeAnswer: C) At a clothing storeExplanation: Given the context of the conversation, with one party inquiring about product details and the other providing information typical of salesinteractions, it is reasonable to conclude that the conversation takes place at a clothing store.3.You will hear a conversation between two friends discussing their weekend plans. Listen and choose the best answer to the question.Question: What does the woman plan to do this weekend?A. Go to the beach.B. Visit her parents.C. Have a picnic with her friends.Answer: B. Visit her parents.Explanation: In the conversation, the woman mentions that she is going to visit her parents this weekend. The other options are not mentioned in the conversation.4.You will hear a short lecture about the importance of exercise. Listen and answer the following question.Question: According to the lecture, what is one of the main benefits of regular exercise?A. Improved concentration.B. Faster metabolism.C. Better sleep.Answer: A. Improved concentration.Explanation: The lecture emphasizes that regular exercise can help improve concentration and mental alertness. The other options are mentioned as benefitsof exercise but not as the main one in this context.5、What time does the train leave?A. 7:00 a.m.B. 8:00 a.m.C. 9:00 a.m.Answer: B. 8:00 a.m.Explanation: In the conversation, the man asks about the departure time of the train, and the woman replies that it leaves at 8 o’clock in the morning. The key information is often found in the response to the inquiry, and in this case, the listener must pay attention to the specific time mentioned.二、听力第二节（本大题有15小题，每小题1.5分，共22.5分）1、A. What are the speakers mainly discussing?B. Why did the woman feel sad last night?C. What does the man suggest doing next?D. How do the speakers know each other?Answer: CExplanation: The man suggests going out for dinner to celebrate, which indicates that they know each other well enough to engage in casual conversation abouta celebration.2、A. What is the main purpose of the call?B. Why did the man miss the appointment?C. What does the woman propose to do next?D. How does the woman feel about the situation?Answer: AExplanation: The woman asks the man if he called to cancel the appointment, which suggests that the main purpose of the call is to discuss the appointment. The man’s response to the question confirms this.3、What does the woman imply about the apartment?A) It’s overpriced.B) It’s very spacious.C) It’s in high demand.D) It’s poorly maintained.Answer: C) It’s in high demand.Explanation: The woman mentions that several people are interested in the apartment and that it might go quickly, indicating that the apartment is popular among potential renters.Question 44、Why does the man want to see the apartment as soon as possible?A) He needs a place to live urgently.B) He is worried about the rent being too high.C) He is concerned about the condition of the apartment.D) He wants to negotiate the terms of the lease.Answer: A) He needs a place to live urgently.Explanation: The man says he needs the apartme nt “as soon as possible,” which suggests that he is in urgent need of a place to live.Please remember that real exam questions would be accompanied by audio recordings, and the conversations would be more complex. The above examples are for illustrative purposes only.5.You will hear a conversation between two students discussing their weekend plans. Listen and answer the question.Question: What activity are the students planning to do together on Sunday afternoon?A) Go to the cinema.B) Have a picnic in the park.C) Visit an art gallery.Answer: B) Have a picnic in the park.Explanation: In the conversation, the students mention that they want to go for a picnic in the park, which suggests that option B is the correct answer.6.You will hear a monologue about the importance of exercise for students. Listen and answer the question.Question: According to the speaker, what is the main benefit of regular exercise for students?A) Improved academic performance.B) Better concentration.C) More energy.Answer: B) Better concentration.Explanation: The speaker emphasizes that regular exercise helps students to concentrate better in their studies, which makes option B the correct answer.7、What does the woman suggest the man do regarding the post office visit?A. Go there immediately.B. Avoid going there after 6 PM.C. Visit after 4 PM to avoid the crowd.D. Take a bus to get there faster.Answer: C. Visit after 4 PM to avoid the crowd.Explanation: The woman suggests visiting the post office after 4 PM because it is less crowded then. She mentions that it’s usually very crowded before 4 PM, implying that it would be better to go after that time.8、When and where are Tom and Lisa planning to meet before their shopping trip?A. At 3 o’clock at the usual café.B. At 3 o’clock at the store.C. At 4 o’clock at the usual café.D. At 4 o’clock at the store.Answer: A. At 3 o’clock at the usual café.Explanation: Tom and Lisa agree to meet at 3 o’clock, and Lisa confirms that she will meet him at the usual café before they start shopping. The meeting place is clearly stated as the café, not the store, and the time is set for 3o’clock.This sample provides a typical format for the listening comprehension part of the English Gaokao, including practical dialogues and relatedmultiple-choice questions.9.You will hear a conversation between two students, Tom and Lisa, discussing their weekend plans. Listen and choose the best answer to the question you will hear.Question: What does Tom decide to do on Sunday?A. He will go to the gym.B. He will visit his grandparents.C. He will go hiking.Answer: BExplanation: In the conversation, Lisa mentions that her grandparents are visiting and Tom responds, “Oh, cool! I’ll join you guys on Sunday.”10.You will hear a short talk about the benefits of exercise. Listen and answer the following question.Question: According to the talk, which of the following is NOT a benefit of regular exercise?A. Improved moodB. Better sleepC. Increased risk of injuryAnswer: CExplanation: The speaker discusses how regular exercise can improve mood, enhance sleep, and boost overall health. However, they do not mention an increased risk of injury as a benefit.11、What is the main topic of the conversation?A. The benefits of morning exercise.B. How to improve one’s diet.C. A discussion about popular sports.D. The importance of a good night’s sleep.Correct Answer: A.Explanation: The speakers mainly discuss the advantages of exercising in the morning, such as improved metabolism and better mood throughout the day. They do not focus on diet improvement, sports popularity, or sleeping habits.12、According to the man, what is an additional benefit of morning workouts besides physical health?A. Enhanced social skills.B. Increased productivity at work.C. Better academic performance.D. Improved cooking abilities.Correct Answer: B.Explanation: During the conversation, the man mentions that he finds himself more productive during his workday when he has exercised in the morning. There is no mention of social skills enhancement, academic performance, or cookingabilities in the context of morning workouts.End of Passage 1Please prepare to listen to Passage 2.Please remember this is a simulated example designed for illustrative purposes only. Real exam questions would come directly from the curriculum and reflect actual topics covered in class.13.You will hear a conversation between two friends discussing their weekend plans. Listen to the conversation and answer the question.Question: What activity do the friends decide to do together this weekend?A) Go hikingB) Visit a museumC) Go swimmingD) Have a picnicAnswer: B) Visit a museumExplanation: In the conversation, the friends talk about their plans for the weekend. They mention that they want to go somewhere educational and fun, which leads them to decide on visiting a museum.14.You will hear a short lecture about the importance of exercise. Listen to the lecture and answer the question.Question: According to the lecture, what is the main benefit of regular exercise?A) Improved memoryB) Better sleepC) Increased productivityD) Lower stress levelsAnswer: D) Lower stress levelsExplanation: In the lecture, the speaker discusses the various benefits of exercise. Although all the options are mentioned as positive outcomes of regular exercise, the main focus is on how it can help lower stress levels, making it the correct answer.15.How much money does the man plan to spend on the new laptop?A.$800.B.$1200.C.$1600.D.$2000.Answer: C.$1600.Explanation: In the conversation, the man mentions that he has saved$800 for the laptop and he needs to borrow another$800 from his friend. Therefore, the total amount he plans to spend is$1600.三、阅读第一节（第1题7.5分，其余每题10分，总37.5分）第一题Read the following passage and answer the questions that follow.In the heart of bustling New York City, there’s a small, quaint bookstorethat has been a staple in the neighborhood for over a century. Known as “The Corner Bookstore,” it is a sanctuary for book lovers, a place where the scent of aged paper and ink intertwines with the sounds of rustling pages and gentle laughter.The store, which occupies a corner of a narrow street, is lined with wooden bookshelves filled with an eclectic mix of books ranging from classic literature to contemporary fiction, poetry, and non-fiction. The owner, Mrs. Thompson, who is in her late sixties, has been running the store for the past forty years. Her passion for literature is evident in every nook and cranny of the shop.One sunny afternoon, a young woman named Emily strolled into the bookstore. She had heard about The Corner Bookstore from a friend and was eager to explore its contents. As she walked through the aisles, she couldn’t help but marvel at the store’s charm and the sense of community that seemed to emanate from every corner.1、What is the primary purpose of the passage?A. To introduce the owner of The Corner BookstoreB. To describe the unique atmosphere of The Corner BookstoreC. To discuss the popularity of bookstores in New York CityD. To explain the history of The Corner Bookstore2、What is the age of Mrs. Thompson?A. 50 years oldB. 60 years oldC. 65 years oldD. 70 years old3、What type of books can be found in The Corner Bookstore?A. Only contemporary fictionB. Only classic literatureC. A mix of classic literature, contemporary fiction, poetry, andnon-fictionD. Only poetry4、Why did Emily visit The Corner Bookstore?A. To buy a new bookB. To meet Mrs. ThompsonC. To experience the unique atmosphereD. To find a specific bookAnswers:1、B2、C3、C4、CQuestion 2:Read the following passage and answer the questions that follow.Passage:In recent years, the Internet has become an integral part of our daily lives.It has revolutionized the way we communicate, access information, and conduct business. However, along with its numerous benefits, the Internet also brings about several challenges.One of the most significant challenges is the issue of online security. With the increasing number of cyber attacks and data breaches, it has become crucial for individuals and organizations to take necessary precautions to protect their personal and sensitive information. This includes using strong passwords, keeping software up to date, and being cautious of phishing scams.Another challenge is the issue of online addiction. Many people spend excessive amounts of time online, which can lead to a range of health problems, including sleep disorders, depression, and anxiety. It is important for individuals to maintain a healthy balance between their online and offline lives.Furthermore, the Internet has given rise to a phenomenon known as “information overload.” With the vast amount of information available online, it can be difficult for individuals to discern what is accurate and reliable. This can lead to misinformation and confusion.Despite these challenges, the Internet continues to be a powerful tool that can greatly enhance our lives. It is essential for us to navigate it responsibly and make the most of its benefits while mitigating its risks.Questions:1、What is the main purpose of the passage?A. To discuss the benefits of the Internet.B. To highlight the challenges of the Internet.C. To argue against the use of the Internet.D. To present a balanced view of the Internet.2、Which of the following is NOT mentioned as a challenge of the Internet?A. Online security issues.B. Health problems due to excessive internet use.C. The availability of free information.D. Misinformation and confusion.3、According to the passage, what is the solution to the problem of online addiction?A. To use the Internet less frequently.B. To maintain a healthy balance between online and offline lives.C. To rely on technology to control internet use.D. To avoid using the Internet altogether.4、The passage suggests that how should individuals navigate the Internet?A. By avoiding it altogether.B. By using it without any precautions.C. By using it responsibly and making the most of its benefits while mitigating its risks.D. By focusing only on the positive aspects of the Internet.Answers:1、B2、C3、B4、C第三题Reading Section ARead the following passage carefully and then answer the questions below.The rise of online shopping has transformed the retail industry. No longer are consumers confined to purchasing goods from physical stores. The convenience and wide variety of products available online have made it a popular choice for many. However, this shift has also brought about several challenges for retailers and consumers alike.One of the major challenges is the issue of counterfeit goods. With the ease of online shopping, it has become increasingly difficult for consumers to distinguish between genuine and fake products. This has led to a significant loss in revenue for both retailers and manufacturers. In response, many companies have started implementing stricter quality control measures and using advanced technology to detect counterfeit items.Another challenge is the environmental impact of online shopping. The massive increase in packaging waste and carbon emissions from deliveries have raised concerns about sustainability. Retailers are now looking for ways to reduce their carbon footprint by offering more sustainable packaging optionsand optimizing delivery routes.Despite these challenges, online shopping continues to grow. One of the reasons for its popularity is the convenience it offers. Consumers can shop from the comfort of their own homes at any time of the day or night. Additionally, online retailers often provide better prices and a wider selection of products compared to brick-and-mortar stores.1、What is the main topic of the passage?A. The benefits of online shoppingB. The challenges of online shoppingC. The history of online shoppingD. The impact of online shopping on the retail industry2、What is a significant challenge mentioned in the passage regarding online shopping?A. The high cost of shippingB. The difficulty in distinguishing between genuine and fake productsC. The lack of customer serviceD. The limited variety of products3、How are companies addressing the issue of counterfeit goods?A. By increasing the price of genuine productsB. By implementing stricter quality control measuresC. By reducing the number of online retailersD. By banning online shopping altogether4、What is one of the reasons for the popularity of online shopping mentioned in the passage?A. The high cost of goodsB. The difficulty in finding parking in physical storesC. The convenience it offersD. The limited availability of productsAnswers:1、B2、B3、B4、C第四题Reading PassageIn the small coastal town of Gull’s Bay, there is a legend that has been passed down through generations. The legend speaks of a hidden treasure buried deep in the sands of the beach. Many adventurers have come to the town in search of this treasure, but none have succeeded. The legend is said to be true, and the treasure is believed to be worth millions of dollars.The story goes like this: A long time ago, a wealthy merchant named Richard sailed from his hometown to Gull’s Bay with a treasure chest filled with gold, jewels, and precious stones. He planned to bury the chest on the beach, but was chased by pirates. In a desperate attempt to escape, Richard buried the chestunder a large rock and ran away, leaving a clue for future generations to find it.The clue was a riddle that reads: “I lie hidden beneath the sand, where the waves come and go. Look to the east and the north, where the sun does not stand. Underneath the rock, you will find, the treasure that I’ve given.”The legend says that the treasure is buried in the exact spot where the sun is not standing, which means it is located at the point where the sun rises and sets at the same time during the summer solstice. This is a very specific spot, and it is said to be near the lighthouse.Questions:1、What is the legend of Gull’s Bay about?A) A treasure buried on the beach.B) A pirate shipwreck.C) A mysterious lighthouse.D) An ancient temple.2、Why did Richard hide the treasure?A) To protect it from the government.B) To hide it from his enemies.C) To leave it for future generations.D) To use it to start a new business.3、What is the clue to finding the treasure?A) A map showing the exact location.B) A riddle that reveals the spot.C) A message left by a previous adventurer.D) A hidden symbol on the beach.4、Where is the treasure believed to be located?A) Near the lighthouse.B) Under the beach sand.C) In the ocean waves.D) On top of the lighthouse.Answers:1、A) A treasure buried on the beach.2、B) To hide it from his enemies.3、B) A riddle that reveals the spot.4、A) Near the lighthouse.四、阅读第二节（12.5分）Reading SectionPassage:The following is an excerpt from a travel article about a famous tourist attraction in China.The Forbidden City, located in the heart of Beijing, was the imperial palace of the Ming and Qing dynasties. It is one of the most well-preserved ancient palaces in the world and is now a museum that showcases the rich history andculture of China. The palace covers an area of 720,000 square meters and has over 870 buildings, including halls, pavilions, and gardens. The walls of the Forbidden City are 860 meters long, and the moat surrounding it is 52 meters wide. The complex was built in 1406 and took 14 years to complete. The Forbidden City is a symbol of the power and wealth of the Chinese emperors and is a must-visit destination for any traveler to China.Questions:1.What is the Forbidden City?A. A modern museum in BeijingB. The imperial palace of the Ming and Qing dynastiesC. A famous restaurant in ChinaD. A popular shopping center in Beijing2.What is the main purpose of the Forbidden City now?A. To serve as the official residence of the Chinese presidentB. To be used as a military baseC. To house the emperors of the Ming and Qing dynastiesD. To be a museum showcasing the rich history and culture of China3.How large is the Forbidden City?A. 720,000 square metersB. 860 meters longC. 52 meters wideD. 14 years to complete4.Who built the Forbidden City?A. The Ming and Qing dynastiesB. The Chinese peopleC. The tourists who visit itD. The United Nations5.What is the Forbidden City a symbol of?A. The beauty of Chinese architectureB. The power and wealth of the Chinese emperorsC. The love of the Chinese people for their historyD. The importance of education in ChinaAnswers:1.B2.D3.A4.A5.B五、语言运用第一节 _ 完形填空（15分）Title: A Day at the ZooThe zoo was a place full of excitement and adventure. It was a sunny Saturday morning, and the park was bustling with visitors. The animals seemed particularly lively that day, and the children were running around in awe oftheir new surroundings.As we entered the zoo, the first exhibit we came across was the big cats. The majestic lions lay in the shade, their golden fur glistening in the sunlight. The cubs, however, were full of energy and played with each other, leaping and chasing.1.The zoo was a place full of excitement and ___________.A. surpriseB. adventureC. sadnessD. boredomWe then moved on to the birdhouse. The colorful birds were perched on the branches, chirping and singing their songs. The peacocks spread their beautiful tails, displaying their vibrant colors for the onlookers.2.The birds in the birdhouse were especially___________that day.A. lazyB. activeC. quietD. shyAs we continued our journey, we reached the reptile house. The snakes slithered gracefully along the ground, and the crocodiles lay still, watching us with their cold, calculating eyes. The children, however, were more interested in the tortoises, who moved at a much slower pace.3.The reptiles in the reptile house were known fortheir___________movements.A. quickB. slowC. energeticD. loudNext, we visited the primates. The apes were playful and intelligent, and the monkeys were acrobats, swinging from branch to branch with ease. The children were amazed by the agility of the primates and enjoyed watching them interact with each other.4.The primates at the zoo were known for their___________behavior.A. calmB. aggressiveC. playfulD. silentAfter a while, we decided to take a break and have some lunch. The zoo provided a picnic area where families could enjoy a meal while watching the animals. We sat under a large tree, eating our sandwiches and watching the zebras graze peacefully nearby.5.The picnic area in the zoo was perfect for visitors to ___________.A. play gamesB. watch animalsC. take photosD. have a mealAs the day came to an end, we made our way back to the entrance. The zoo had been a memorable experience, and we couldn’t wait to return. The animals had taught us about their behaviors and habits, and the children had gained a deeper appreciation for wildlife.6.Our visit to the zoo was a___________experience for us all.A. boringB. thrillingC. frustratingD. forgettableAnswer Key:1.B. adventure2.B. active3.B. slow4.C. playful5.D. have a meal6.B. thrilling六、语言运用第二节 _ 语法填空（15分）Read the following passage. For each blank, choose the best answer from the four choices given.One of the most fascinating aspects of the English language is its ability to evolve and adapt. Over the centuries, it has absorbed words from many different languages, including Latin, Greek, French, and German. This process is known as 1.. It’s not just words that change, 2.. Grammar and pronunciation also adapt to the needs of the speakers. For example, the word “neighbor” comes from Old English, but its pronunciation has changed over time. Similarly, the verb “to do” has several different past forms, such as “did,” “done,” and “done.” This 3. reflects the language’s flexibility and its responsiveness to the way people actually speak.One of the most interesting examples of language change is the 4. of the word “OK.” It originated in the United States in the 1830s and was created as an abbreviation for “oll korrect.” Over time, it has become a universally recognized term of approval. The 5. of this word demonstrates how a simple abbreviation can gain widespread acceptance and become an integral part of the language.Language change is also evident in the way we use 6.. For instance, the word “email” used to be written as “e-mail,” but now it is commonly written without the hyphen. This change reflects the evolving conventions of written English.The 7. of language change can be attributed to several factors. One of the main reasons is the 8. of people and ideas. As societies become more interconnected, languages naturally borrow words and phrases from one another.Another factor is the 9. of technology, which allows for the rapid spread of new words and phrases. Lastly, the 10. of language itself is another reason for its continuous evolution.Choose the best answer for each blank:1.A) borrowingB) adaptationC) evolutionD) transformation2.A) its structureB) its meaningC) its originD) its pronunciation3.A) diversityB) consistencyC) simplicityD) complexity4.A) originB) pronunciationC) usageD) spelling5.A) acceptanceB) rejectionC) evolutionD) pronunciation6.A) nounsB) verbsC) adjectivesD) pronouns7.A) processB) impactC) reasonD) challenge8.A) movementB) exchangeC) influenceD) development9.A) innovationB) improvementC) expansionD) advancement10.A) adaptabilityB) reliabilityC) stabilityD) flexibilityAnswer key:1.C) evolution2.A) its structure3.A) diversity4.A) origin5.A) acceptance6.C) adjectives7.A) process8.B) exchange9.D) advancement10.A) adaptability七、写作第一节 _ 应用文写作（15分）写作题目：You have recently returned from a short trip to a famous tourist destination. Write a letter to a friend who is planning to visit the same place soon. In your letter, include the following points:1.Briefly describe your visit.2.Share your favorite experience or place.3.Offer suggestions for activities or places to visit.4.Mention any tips or advice you have for them.Writing Example:Dear [Friend’s Name],I hope this letter finds you well! I just wanted to share with you my recent trip to [Tourist Destination], which was absolutely incredible. I’m sure you’ll be excited to hear about it, especially since you’re planning your own trip there soon.I arrived in [Tourist Destination] on a sunny Saturday morning. The city was bustling with activity, and the scenery was breathtaking. My favorite experience was visiting the [Famous Landmark or Attraction], which is a must-see for anyone visiting the area. The architecture was stunning, and the views from the top were just phenomenal.I spent the afternoon exploring the nearby [Local Market or Park], where I tried some delicious local cuisine and bought some unique souvenirs. One of the highlights was trying the [Specific Food or Drink], which was both tasty and a cultural experience in itself.For activities, I would highly recommend taking a hike up [Mountain or Hill], as the trail offers some of the most spectacular views of the city and surrounding landscape. If you’re interested in history, the [Historical Museum or Site] is a great place to learn about the area’s past.Here are a few tips I’ve gathered:1.Don’t miss out on the [Specific Event or Festival] if it’s happening during your visit; it’sa fantastic way to experience the local culture.2.Always carry a map or have a GPS on hand, as some areas can be quite hilly and the streets can be confusing.3.Stay hydrated and wear comfortable shoes, as you’ll be doing a lot of。
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2 The Bayes Premium
The idea of “as well as possible” is made precise by the introduction of a loss function : L(&, T (x)) : loss, if & is the “true” parameter and T (x) is the value taken by the estimator when the value x is observed. From this we derive the risk function of the estimator T Z RT (&) := E& [L(&, T )] = L(&, T (x)) dF& (x).
2.2 Bayes Risk and Bayes Estimator
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Definition 2.1. We define the Bayes risk of the estimator T with respect to the a priori distribution U (&) as Z R(T ) := RT (&)dU (&).
Rn
(2.1)
(Only such functions T and L are allowed for which the right-hand side of (2.1) exists.) The goal then is to find an estimator T 5 D, for which the risk RT (&) is as small as possible. In general, it is not possible to do this simultaneously for all values of &. In other words, in general there is no T which minimizes RT (&) uniformly over &. In Figure 2.1 we see an example, where depending on the value of &, T1 or T2 has the smaller value of the risk function.
Rn
From this we deduce the following rule for constructing the Bayes estimator: ] Theorem R 2.3. For every possible observation x, T (x) takes the value which minimizes L(&, T (x))dUx (&). In other words, for every possible observation ] x, T (x) is the Bayes estimator with respect to the distribution Ux (&). Terminology: In Bayesian statistics, U (&) is called the a priori distribution of (before observations have been made), Ux (&) is called the a posteriori distribution of (after observations have been made).
2 The Bayes Premium
In this chapter we will study the best experience premium or Bayes premium, which we defined in (1.3), ] P Bayes := µ () = E [ µ()| X] . To do this, we will use concepts from statistical decision theory. In particular, we will see in exactly which sense P Bayes is “best” and why it is called the Bayes premium.
R T1 (- ) R T2 (- )
Fig. 2.1. Risk functions RT1 and RT2 for T1 and T2
2.2 Bayes Risk and Bayes Estimator
In Bayesian statistics, a smoothed average of the curve RT (&) is considered, where the average is weighted by means of a probability distribution U (&) (called an a priori distribution for ). In other words, we consider the expected value of RT (), by regarding & as the realization of a random variable with probability distribution U .
2.1 Basic Elements of Statistical Decision Theory
Here we will give an overview of the elements of statistical decision theory which will be necessary for our exposition. For a comprehensive study of statistical decision theory, see for example Lehmann [Leh86]. The raw material for a statistical decision is the observation vector X = (X1 , X2 , . . . , Xn )0 . The distribution function F& (x) = P& [X x] is completely or partly unknown. (Equivalently: The parameter & is completely or partly unknown.) We are interested in the value of a specific functional g (&) of the parameter &. We seek a function T (X), which depends only on the observation vector X, which will estimate g (&) “as well as possible”. The function T (X) is called an estimator for g (&). We will formulate this problem in the following way: & 5 : The set of parameters, which contains the true value of &, T 5 D: The set of functions to which the estimator function must belong. T is a map from the observation space Rn into the set of all possible values of the functional g, that is, the set {g (&) : & 5 }.
x5D
e as Definition 2.2. We define the Bayes estimator T e := arg min R(T ), T
T 5D1
(2.2)
where D1 is the set of all mathematically allowable estimators (that is, those estimators with integrable risk functions). e is that estimator (2.2) which minimizes the Bayes risk R(·). The estimator T Without further ado, we assume that minT 5D1 R(T ) is attained (this will indeed always be the case in the situations that we consider here in this book). A remark on the notation: We use P to denote the joint distribution of (, X), F to denote the marginal distribution of X and Ux to denote the conditional distribution of , given X = x. In order to construct the Bayes estimator, we consider the following sequence of equations: Z Z R(T ) = RT (&)dU (&) = E& [L(&, T )] dU (&) Z Z L(&, T (x))dF& (x)dU (&) = Rn Z Z L(&, T (x))dUx (&)dF (x). =