统计学试卷国际学院英文

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上外贤达学院概率论与数理统计第一学期(英文版)试卷-推荐下载

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3.(15%)A machine produces defective parts with three different probabilities
depending on its state of repair. If the machine is in good working order,it produces defective parts with probability 0.02. If it is wearing down, it produces defective parts with probability 0.1. If it needs maintenance, it produces defective parts with probability 0.3. The probability that the machine is in good working order is 0.8, the probability that it is wearing down is 0 .1, and the probability that it needs maintenance is 0.1. Compute the probability that a randomly selected part will be defective. 一台机器生产不合格部件的概率与机器所处的状态有关。如果机器处于比较好的工作状态，则该概率为 0.02；如果机器处于磨损状态，则该概率为 0.1；如果机器需要维修，则该概率为 0.3. 而机器处于比较好的工作状态的概率为 0.8，处于磨损状态的概率为 0.1，处于需要维修状态的概率为 0.1.求随机选择一个部件，该部件为不合格品的概率。 4 (10%)Two students A and B are both registered for a certain course. Assume that student A attends class 80 percent of the time, student B attends class 60 percent of the time, and the absences of the two students are independent. a What is the probability that at least one of the two students will be in class on a given day? b If at least one of the two students is in class on a given day, what is the probability that A is in class that day? 两个学生 A 和 B 都选了同一门课。假定学生 A 的出勤率为 80%，学生 B 的出勤率为 60%，两个学生是否出勤是相互独立的。求（a）某一天至少有一个学生出勤的概率；（b）假定某一天至少有一个学生出勤，求出勤的学生是 A 的概率。

国际学校英文考试题及答案

国际学校英文考试题及答案一、选择题（每题2分，共20分）1. Which of the following is the correct spelling of the word "library"?A. libaryB. librayC. libraryD. libray答案：C2. The sentence "She is a quick learner" means:A. She learns slowly.B. She learns quickly.C. She doesn't like learning.D. She is not a good learner.答案：B3. Fill in the blank: "I will _______ you at the airport tomorrow."A. meetB. meetsC. meetingD. met答案：A4. What is the past tense of "write"?A. wroteB. writedC. writesD. writing答案：A5. Choose the correct preposition to complete the sentence: "She is standing _______ the window."A. inB. onC. atD. by答案：D6. Which of the following is the comparative form of the adjective "big"?A. biggerB. bigC. biglyD. bigness答案：A7. The verb "to be" in the present continuous tense is:A. amB. isC. areD. be答案：A8. What is the opposite of "agree"?A. disagreeB. agreeC. agreeableD. disagreeable答案：A9. Complete the sentence with the correct article: "_______ cat is on the mat."A. AB. AnC. TheD. /答案：C10. Which word is a synonym for "unusual"?A. commonB. normalC. regularD. rare答案：D二、填空题（每题2分，共20分）11. The word "opposite" has _______ syllables.答案：312. The present tense of "to eat" is _______.答案：eat13. "The _______ of the meeting has been changed to next week."答案：date14. "She is _______ than her sister."答案：taller15. "Please _______ the book on the table."答案：put16. "He _______ to the concert last night."答案：went17. "We _______ to the beach yesterday."答案：went18. "I _______ my homework last night."答案：did19. "They _______ the house."答案：cleaned20. "She _______ her keys in the car."答案：left三、阅读理解（每题2分，共20分）阅读下面的短文，并回答问题。

英文统计学真题及答案解析

英文统计学真题及答案解析统计学是一门研究如何收集、分析、解释和展示数据的学科。

它涉及到各种统计方法和技术，可应用于多个领域，如经济学、医学、环境科学等。

对于学习统计学的人来说，熟悉真题并且了解其解答是非常重要的。

本文将介绍一些英文统计学真题，并对其答案进行解析。

题目1：A survey was conducted to determine the average hours of sleep that adults in a certain city get per night. Theresults of the survey were as follows: 6, 7, 5, 8, 6, 7, 6, 9, 5, 7. Calculate the mean, median, and mode of the data.解析1：Mean（均值）是数据的平均值，可以通过将所有数值相加并除以数据的个数来计算。

在这个例子中，我们将6 + 7 + 5 + 8 + 6 + 7 + 6 + 9 + 5 + 7 = 66，然后除以10（数据的个数），得到的均值为6.6小时。

Median（中位数）是按顺序排列的数据集中的中间值。

在这个例子中，我们将数据从小到大排列为5, 5, 6, 6, 6, 7, 7, 7, 8, 9。

可以看出，中间的数值是6和7。

因此，中位数是6.5小时。

Mode（众数）是数据集中出现次数最多的值。

在这个例子中，有3个6和3个7，其余的数值只出现了1次。

因此，6和7都是众数。

题目2：A researcher is investigating the relationship between education level and income. She collects data from a random sample of 100 individuals and obtains the following results:20 individuals have a high school diploma and earn an average income of $30,000, 50 individuals have a bachelor's degreeand earn an average income of $40,000, and 30 individualshave a master's degree and earn an average income of $50,000. Calculate the weighted mean income for this sample.解析2：Weighted mean（加权均值）是根据不同的权重计算出的平均值。

高三英语统计学分析练习题30题

高三英语统计学分析练习题30题1.The number of correct answers in the exam is an important indicator.A.amountB.quantityC.sumD.number答案：D。

“number”侧重于可数名词的数量；“amount”和“quantity”一般用于不可数名词的数量；“sum”表示总数，总和，一般不用于此处语境。

2.The percentage of students passing the exam is calculated by dividing the number of students who passed by the total number of students.A.proportionB.ratioC.rateD.percentage答案：D。

“percentage”表示百分比；“proportion”表示比例，强调部分与整体的关系；“ratio”强调两个数的比；“rate”一般指比率，速度等。

3.The average score of the class can be obtained by adding up all the scores and dividing by the total number of students.A.medianB.meanD.average答案：D。

“average”表示平均数；“median”是中位数；“mean”在某些语境下也可以表示平均数，但不如“average”常用；“mode”是众数。

4.The range of scores shows the difference between the highest and lowest scores.A.extentB.spanC.rangeD.distance答案：C。

“range”表示范围；“extent”强调程度，范围；“span”一般指跨度；“distance”是距离。

统计学试卷(国际学院-英文)

江西财经大学试卷试卷代码: A 课程学时:48课程名称:统计学适用对象:1。

Single selection(1 point per question, 10 points total)1．Which option below is a continuous indicator？（C ）A、Number of employeesB、Number of machinesC、Gross industrial output valueD、Number of workshops2．Which ratio below represents the largest variance?（ B ).A、0。

7B、0。

5C、0。

1D、0.43．Assuming a population with normal distribution。

In order to estimate the interval of its mean value，which statistic should be used if only a small sample is available? ( C )A、Normal statisticB、χ2statisticC、t statisticD、F statistic4．If all observed data values fall on the regression line，then the correlation between these two variables is( C ）。

A、1B、—1C、+1 or —1D、05．Sampling standard variance （eg。

) shows the ( C ）between sample indicator and population indicatorA、Real errorB、Absolute value of real errorC、Average level of errorD、Possible level of error6．If we know the of a linear regression is 0.64，then the residual sum of squares occupies a proportion of ( A ）in the total sum of squares.A、0.36B、0。

2022级统计学专业外语试题及答案

一．选择题(每题1分，共10分)1. Categorical data can be further divided into nominal and _D__ data.A. quantitativeB. scaleC. qualitativeD. ordinal2. For a sample with the data {10,8,20,25,12}, the sample mean is __B__A. 14B. 15C. 16D. 173. Let X be Binomial(4,0.5), then P(X=0) is __A__A. 1/8B. 1/4C. 1/16D. 1/24. Which number is the square of some integer? DA. 6B. 7C. 8D. 95. The range for the Pearson correlation coefficient is__B__<BC一样>A. [0,1]B. [-1,1]C. [-1,1]D. [-1,0]6. Which of the following is NOT used to a measure of central tendency?CA. meanB. medianC. modeD. variance7. Which of the following is a method of statistical inference? DA. meanB. frequency tableC. box-plotD. t-test8. Let X,Y be the two random variable,which of the following is TRUE? BA. E(X-Y)=EX-EYB. E(XY)=EXEYC. E(X/Y)=EX/EYD. Var(X+Y)=Var(X)+Var(Y)9. What does the abbreviation s.t. stands for? DA. that is C. for exampleC. such thatD. because10.What does the abbreviation i.e. stands for? AA. that is C. for exampleC. such thatD. because二．将下面的统计术语翻译成中文或者英文(每题1分，共20分)1. Probability 概率2. Statistics 统计学3. Statistical models 统计模型4. Multiple regression 多元回归5. Bernoulli distribution 伯努利分布6. Time Series 时间序列7. Multicollinearity 多重共线性8. Density function 密度函数9. Histogram 直方图10. Random variable 随机变量11. 描述性统计Descriptive statistics12. 点估计Point estimate13. 正态分布Normal distribution14. 样本sample15. 总体overall16. 假设检验hypothetical test17. 实验设计experimental design18. 方差分析variance analysis19. 中心极限定理Central limit theorem20. 渐近正态性Asymptotic normality三．将下面的句子翻译成英文(每题4分，共20分)1.统计学是一门收集，整理，分析和解释数据的学科答：Statistics is a discipline that collects, organizes, analyzes, and interprets data.2.X1, X2… X n是一列独立同分布的随机变量。

2021统计学第一学期期末考试试卷C(英文版)

江西财经大学2021统计学第一学期期末考试试卷C(英文版)Ⅰ、SINGLE CHOICE (1′×10＝10′)1、The emphatic unit in emphatic survey is ( )A the unit which has emphatic meaning or representationB the unit which has emphatic meaning in managementC the unit which can infer the populationD the unit which total index has the vast majority proportion in the population2、In frequency distribution, the frequency of close to middle is small, the frequency of close to extremity is large, this distribution is ( )?A bell-shaped distributionB U-shaped distributionC J-shaped distributionD Lorenz distribution3、Compare cluster sampling and other sampling methods with the same sample size, the sample error of cluster sampling is ( )A largerB smallerC equalD inverse4、A time series has 30 years' data, we use moving average to determine the long tendency, if we use 5 years moving average, how many years’ data does the series have after amend ?A 30B 28C 26D 255、Suppose you are doing a interval estimate of a population rate, the data of population is unknown, the variance of the rate has no data, and can’t calculate by the sample. Now, the variance should be valued by ( )A 30%B 25%C 40%D 50%6、Which regression equation is confirm wrong ( )?A.x y32ˆ+= r=0.88 B.x y54ˆ+= r=0.55 C.x y510ˆ+-= r=－0.90 D.x y90.0100ˆ--= r=-0.837、The standard error of the estimate reflects ( )A the representation of the meanB correlative relationshipC the representation of the regression lineD the representation of the 序时平均数8、The data of 100 workers’ products per day illustrate the largest is 38, the smallest is 19, if we classify this 100 workers by products per day into 5 groups with a same distance, the distance between groups should be ( )?A 3B 4C 8D 109、We sample by area that divided by geography, the sampling method is ( )A pure random samplingB equidistant samplingC type samplingD cluster sampling10、In a small -sample case, the degrees of freedom when we inspect t -distribution must determined by( )A n -1B n -2C n -3D n -the number of parameter in regression equation.Ⅱ、JUDGE (Write “T” for true and “F” for false. 1′×10＝10′)1、The classify method according to two or more than two index is simple classification.（）2、Mode is the greatest frequency occurred in the population. ( )3、Unit cost is a quantity index. ( )4、The formula of Paasche index weight for each item is its report-period quantity. ( )5、The distribution of investment by profit is a J –shaped distribution ( )6、To the population, it is necessary to statistic whether it exist variance. ( )7、The food output of a area is 4 million tons in 2005, and it plans to amount to 4.5 million tons in 2009, the year’s average increasing rate of the food output during 2006~2009 is 2.99%. ( )8、The weight of arithmetical mean can be expressed by relative number, also can be expressed by absolute number, the results are equal. ( )9、In sampling and inference, the accuracy and the confidence indicate are change in the same direction. ( )10、In the linear regression equation, the absolute value of the regression Coefficient is determined by the size of the variable’s measurement unit. ( )Ⅲ、SIMPLE ANSWER（5′×2=10′）1 Briefly describes the basic ideology of interval estimation.2 Generally relate the basic contents of time series analyze and statistical index analyze.Ⅳ、CALCULATION（15′×3=45′）1、There is two classes take part in statistical examine, the average score of class one is 81,and the standard deviation is 9.9,the data of class two is given as follows: (15’)Score Number of students60以下460—70 1070—80 2080—90 1490—100 2Total 50questions：(1)calculate the average score and the standard deviation of class two；(2) Compare the average scores of the two classes, and point out which one is mare representative.2、We sample 100 spare parts randomly by replacement sampling. The result is: the average length is 10 millimeter; the standard deviation is 0.15 millimeter. Questions (1) provide a 95.45% confidence interval for the average length of this lot of spare parts;(2) Assume other conditions are invariant; decrease half of the margin of error, how many spare parts should be sampled? (15’)3、Gross value of industrial output and staff population of a company in 2006 areand：the staff population at the end of 2005 is 2010。

银川海派英语【SAT2数学】概率与统计学习题

银川海派英语【SAT2数学】概率与统计学习题扫描下方二维码关注海派国际英语官方微信公众账号，更多精彩内容不容错过！！SAT Math Statistics and Probability ReviewAverages are a statistics that are used to get information on a set of data.The arithmetic mean of a set of n numbers is equal to the sum of the numbers divided by n. SAT math questions that use the word average refer to the arithmetic mean.For example the arithmetic mean of 4 5 and 9 will be (4 + 5 + 9)/3 = 6.Example of SAT question using the arithmetic mean: The average of the integers 24 6 12 x and y is 11. What is the value of the sum x + y?(a) 11(b) 17(c) 13(d) 15Answer: The average of the 5 numbers is (24 + 6 + 12 + x + y)/5. This should be equal to 11 according to the problem so24 + 6 + 12 + x + y = 11 ? 5 = 55x + y = 55 - 24 - 6 - 12 = 13The median of a set of numbers is the number in the middle when the numbers are ordered. For example the median of (1 5 2 7 and 10) is 5 because when the numbers are ordered 5 is in the middle When there is an even number of values the median is the same as the mean of the two middle numbers.The mode of a set of numbers is the number that occurs most often in the list. For example 75 is the mode of 24 75 55 84 75 and 12. A list of numbers can have more than one mode for example (22 24 22 25 24 27 27 29) has 3 modes 22 24 and 27.Example of SAT question using statistics: A parameter is measured during a scientific experiment and the results are -12 4 -8 10 2 2 0 -4 and 2. The median and the average of these numbers are:(a) median = 0 average = -4/9(b) median = 0 average = 4/9(c) median = 2 average = -4/9(d) median = 2 average = 4/9(e) median = 2 average = 2/9Answer: You may arrange the numbers in order: -12 -8 -4 0 2 2 2 4 and 10. The median will be number in the middle of the row that is The average will be (-12-8-4+0+2+2+2+4+10)/9 = -4/9. The correct answer is (c)Probability is the likelihood or chance that something is the case or will happen. A probability may be expressed as either a decimal or a fraction.If the probability is 0 the event can never occur and if the probability is 1 the event is certain to occur.If the probability is between 0 and 1 that number expresses the likelihood of occurrence.Example of SAT exercise with probability: If a is an integer chosen randomly from the set {3 4 5 9} and b is an integer chosen randomly from the set {3 8 12 15} what is the probability that a/b is an integer?(a) .25(b) .2(c) .125(d) .375(e) .4Answer: We have 4 possible integers for a and 4 for b so the number of possible combinations for (a / b) is 1a/b is an integer only for 2 combinations1. a = 3 and b = 1. a = 9 and b = 3 The probability that a/b is an integer is 2/16 = 1/8 = .125. (c) is the correct answer.上面整理的就是SAT2数学概率与统计学习题，希望对大家考试有帮助。

上海民办协和双语尚音学校必修第二册第四单元《统计》检测题(有答案解析)

一、选择题1．某高校大一新生中,来自东部地区的学生有2400人、中部地区学生有1600人、西部地区学生有1000人.从中选取100人作样本调研饮食习惯,为保证调研结果相对准确,下列判断正确的有（）①用分层抽样的方法分别抽取东部地区学生48人、中部地区学生32人、西部地区学生20人；②用简单随机抽样的方法从新生中选出100人；③西部地区学生小刘被选中的概率为1 50；④中部地区学生小张被选中的概率为1 5000A．①④B．①③C．②④D．②③2．某工厂生产甲、乙、丙、丁四种不同型号的产品，产量分别为200400300100,,,件，为检验产品的质量，现用分层抽样的方法从以上所有的产品中抽取60件进行检验，则应从丙种型号的产品中抽取（）件．A．24 B．18 C．12 D．63．2020年春节后，因受疫情影响，某高中学校为学生导学助学开展网课，为了解网课教学方式对学生视力影响情况，在学校抽取了100名同学进行视力调查.如图为这100名同学视力的频率分布直方图，其中前4组的频率成等比数列，后6组的频数成等差数列，设最大频率为a，在4.6到5.0之间的数据个数为b，则a b、的值分别为（）A．0.27,78B．0.27,73C．2.7,78D．2.7,734．某赛季甲、乙两名篮球运动员每场比赛得分用茎叶图表示，茎叶图中甲得分的部分数据被墨迹污损不清（如图1），但甲得分的折线图完好（如图2），则下列结论错误的是（）A．乙运动员得分的中位数是17，甲运动员得分的极差是19 B．甲运动员发挥的稳定性比乙运动员发挥的稳定性差C．甲运动员得分有12的叶集中在茎1上D．甲运动员得分的平均值一定比乙运动员得分的平均值低5．2019年是中国成立70周年，也是全面建成小康社会的关键之年.为了迎祖国70周年生日，全民齐心奋力建设小康社会，某校特举办“喜迎国庆，共建小康”知识竞赛活动.下面的茎叶图是参赛两组选手答题得分情况，则下列说法正确的是（）A．甲组选手得分的平均数小于乙组选手的平均数B．甲组选手得分的中位数大于乙组选手的中位数C．甲组选手得分的中位数等于乙组选手的中位数D．甲组选手得分的方差大于乙组选手的的方差6．一位学生在计算20个数据的平均数时，错把68输成86，那么由此求出的平均数与实际平均数的差为A．B．C．D．7．某单位青年、中年、老年职员的人数之比为10∶8∶7，从中抽取200名职员作为样本，若每人被抽取的概率是0.2，则该单位青年职员的人数为()A．280 B．320 C．400 D．10008．如图所示是2018年11月份至2019年10月份的居民消费价格指数(()%CPI)与工业品出厂价格指数(()%PPI)的曲线图，从图中得出下面四种说法：①()%CPI 指数比相应时期的()%PPI 指数值要大； ②2019年10月份()%CPI 与()%PPI 之差最大；③2018年11月至2019年10月()%CPI 的方差大于()%PPI 的方差﹔ ④2018年11月份到2019年10月份的()%PPI 的中位数大于0. 则说法正确的个数为（） A ．1B ．2C ．3D ．49．已知一组数据：123,,,,n x x x x 的平均数为4，方差为10，则1232,32,32n x x x ---的平均数和方差分别是（）A ．10，90B ．4，12C ．4，10D ．10，1010．如图是民航部门统计的2018年春运期间十二个城市售出的往返机票的平均价格以及相比去年同期变化幅度的数据统计图表，根据图表，下面叙述不正确的是（）A ．变化幅度从高到低居于后两位的城市为北京，深圳B ．天津的变化幅度最大，北京的平均价格最高C ．北京的平均价格同去年相比有所上升，深圳的平均价格同去年相比有所下降D ．厦门的平均价格最低，且相比去年同期降解最大11．甲、乙两名同学在5次数学考试中，成绩统计图用茎叶图表示如图所示，若甲、乙两人的平均成绩分别用x 甲、x 乙表示，则下列结论正确的是( )A ．x x >甲乙，且甲比乙成绩稳定B ．x x >甲乙，且乙比甲成绩稳定C ．x x <甲乙，且甲比乙成绩稳定D ．x x <甲乙，且乙比甲成绩稳定12．某公司10位员工的月工资（单位：元）为1x ，2x ，…，10x ，其均值和方差分别为x 和2s ，若从下月起每位员工的月工资增加100元，则这10位员工下月工资的均值和方差分别为（） A ．x ，22s 100+ B ．100x +，22s 100+ C ．x ，2sD ．100x +，2s13．设样本数据1210,,,x x x 的均值和方差分别为1和4，若(i i y x a a =+为非零常数，1,2,,10)i =，则1210,,,y y y 的均值和方差分别为（）A ．1,4a +B ．1,4a a ++C ．1,4D ．1,4a +二、解答题14．某中学组织了地理知识竞赛，从参加考试的学生中抽出40名学生，将其成绩（均为整数）分成六组[)40,50，[)50,60，…，[]90,100，其部分频率分布直方图如图所示．观察图形，回答下列问题．（1）求成绩在[)70,80的频率，并补全这个频率分布直方图；（2）估计这次考试的平均分（计算时可以用组中值代替各组数据的平均值）；（3）从成绩在[)40,50和[]90,100的学生中选两人，求他们在同一分数段的概率． 15．随机观测生产某种零件的某工厂25名工人的日加工零件数（单位：件），获得数据如下：30、42、41、36、44、40、37、37、25、45、29、43、31、36、49、34、33、43、38、42、32、34、46、39、36，根据上述数据得到样本的频率分布表如下：分组频数频率[]25,303 0.12(]30,3550.20(]35,4080.32(]40,451n1f(]45,502n2f（1）确定样本频率分布表中1n、2n、1f和2f的值；（2）根据上述频率分布表，画出样本频率分布直方图；（3）根据样本频率分布直方图，求在该厂任取4人，至少有1人的日加工零件数落在区间(]30,35的概率.16．某高校共有学生15000人，其中男生10500人，女生4500人.为调查该校学生每周平均体育运动时间的情况，采用分层抽样的方法，收集300位学生每周平均体育运动时间的样本数据（单位：小时）.（1）应收集多少位女生的样本数据？（2）根据这300个样本数据，得到学生每周平均体育运动时间的频率分布直方图（如图所示），其中样本数据的分组区间为：[]0,2，(]2,4，(]4,6，(]6,8，(]8,10，(]10,12.估计该校学生每周平均体育运动时间超过4小时的概率.（3）在样本数据中，有60位女生的每周平均体育运动时间超过4小时，请完成每周平均体育运动时间与性别列联表，并判断是否有95%的把握认为“该校学生的每周平均体育运动时间与性别有关”.()2P K k≥0.100.050.0100.005附：()()()()() 2n ad bcKa b c d a c b d-=++++.17．2019年，我国施行个人所得税专项附加扣除办法，涉及子女教育、继续教育、大病医疗、住房贷款利息或者住房租金、赡养老人等六项专项附加扣除.某单位老、中、青员工分别有72，108，120人，现采用分层抽样的方法，从该单位上述员工中抽取25人调查专项附加扣除的享受情况.（2）抽取的25人中，享受至少两项专项附加扣除的员工有6人，分别记为A，B，C，D，E，F.享受情况如下表，其中“○”表示享受，“×”表示不享受.现从这6人中随机抽取2人接受采访.①试用所给字母列举出所有可能的抽取结果；②设M为事件“抽取的2人享受的专项附加扣除至少有一项相同”，求事件M发生的概率. 18．某学习小组在研究性学习中,对昼夜温差大小与绿豆种子一天内出芽数之间的关系进行研究.该小组在4月份记录了1日至6日每天昼夜最高、最低温度(如图1),以及浸泡的100颗绿豆种子当天内的出芽数(如图2).根据上述数据作出散点图,可知绿豆种子出芽数y (颗)和温差x (0C )具有线性相关关系. (1)求绿豆种子出芽数y (颗)关于温差x (0C )的回归方程y bx a =+；(2)假如4月1日至7日的日温差的平均值为110C ,估计4月7日浸泡的10000颗绿豆种子一天内的出芽数.附：121()()()niii nii x x y y b x x ==--=-∑∑1221ni ii ni i x y nxyx nx ==-=-∑∑，a y bx =-19．研究发现，北京 PM 2.5 的重要来源有土壤尘、燃煤、生物质燃烧、汽车尾气与垃圾焚烧、工业污染和二次无机气溶胶，其中燃煤的平均贡献占比约为 18%．为实现“节能减排”，还人民“碧水蓝天”，北京市推行“煤改电”工程，采用空气源热泵作为冬天供暖．进入冬季以来，该市居民用电量逐渐增加，为保证居民取暖，市供电部门对该市 100 户居民冬季（按 120 天计算）取暖用电量（单位：度）进行统计分析，得到居民冬季取暖用电量的频率分布直方图如图所示．（1）求频率分布直方图中a 的值；（2）从这 100 户居民中随机抽取 1 户进行深度调查，求这户居民冬季取暖用电量在[3300,3400]的概率；（3）在用电量为[3200,3250)，[3250,3300)，[3300,3350)，[3350,3400]的四组居民中，用分层抽样的方法抽取 34 户居民进行调查，则应从用电量在[3200,3250)的居民中抽取多少户？ 20．在某市高中某学科竞赛中，某一个区4000名考生的参赛成绩统计如图所示.（1）求这4000名考生的竞赛平均成绩x （同一组中数据用该组区间中点作代表）；（2）由直方图可认为考生竞赛成绩z 服正态分布2(,)N μσ，其中μ，2σ分别取考生的平均成绩x 和考生成绩的方差2s ，那么该区4000名考生成绩超过84.81分（含84.81分）的人数估计有多少人？（3）如果用该区参赛考生成绩的情况来估计全市的参赛考生的成绩情况，现从全市参赛考生中随机抽取4名考生，记成绩不超过．．．84.81分的考生人数为ξ，求(3)P ξ≤.（精确到0.001）附：①2204.75s =，204.7514.31=；②2(,)zN μσ，则()0.6826P z μσμσ-<<+=，(22)0.9544P z μσμσ-<<+=；③40.84130.501=.21．某校高二文科分四个班，各班人数恰好成等差数列，高二数学调研测试后，对四个文科班的学生试卷按每班人数进行分层抽样，对测试成绩进行统计，人数最少的班抽取了22人，抽取的所有学生成绩分为6组：[70,80)，[80,90)，[90,100)，[100,110)，[110,120)，[120,130)，得到如图所示的频率分布直方图，其中第六组分数段的人数为5人．（1）求a 的值，并求出各班抽取的学生数各为多少人？（2）在抽取的学生中，任取一名学生，求分数不小于90分的概率（视频率为概率）．（3）估计高二文科四个班数学成绩的平均分22．某中学从高三男生中随机抽取100名学生，将他们的身高数据进行整理，得到下侧的频率分布表.组号分组频率第1组[160，165）0.05第2组[165,170)0.35第3组[170,175)0.3第4组[175,180)0.2第5组[180,185]0.1合计 1.00（Ⅰ）为了能对学生的体能做进一步了解，该校决定在第3，4，5组中用分层抽样的方法抽取6名学生进行体能测试，问第3，4，5组每组各应抽取多少名学生进行测试；（Ⅱ）在（Ⅰ）的前提下，学校决定在6名学生中随机抽取2名学生进行引体向上测试，求第3组中至少有一名学生被抽中的概率；（Ⅲ）试估计该中学高三年级男生身高的中位数位于第几组中，并说明理由.23．节能减排以来，兰州市100户居民的月平均用电量(单位：度)，以[)[)[)[)[)[)[] 160180180200200220220240240260260280280300，，，，，，，，，，，，，分组的频率分布直方图如图．()1求直方图中x的值；()2求月平均用电量的众数和中位数；()3估计用电量落在[)，中的概率是多少？22030024．有一容量为50的样本,数据的分组以及各组的频数如下:[12.5,15.5),3;[15.5,18.5),8;[18.5,21.5),9;[21.5,24.5),11;[24.5,27.5),10;[27.5,30.5),5;[30.5,33.5],4.(1)列出样本的频率分布表.(2)画出频率分布直方图.(3)根据频率分布表,估计数据落在[15.5,24.5)内的可能性约是多少?25．某市电力公司为了制定节电方案，需要了解居民用电情况，通过随机抽样，电力公司获得了50户居民的月平均用电量，分为六组制出频率分布表和频率分布直方图（如图所示）.组号分组频数频率1[0,200)20.042[200,400)e f[600)140.28 3400,4[600,800)c d5[800,1000)a b6[1000,1200]40.08（1）求a，b的值；（2）为了解用电量较大的用户用电情况，在第5、6两组用分层抽样的方法选取5户.①求第5、6两组各取多少户？②若再从这5户中随机选出2户进行入户了解用电情况，求这2户中至少有一户月平均用电量在[1000,1200]范围内的概率.26．为了了解甲、一两个工厂生产的轮胎的宽度说法达标，分别从两厂随机个选取了10个轮胎，经每个轮胎的宽度（单位：mm）记录下来并绘制出如下的折线图：（1）分别计算甲、乙两厂提供10个轮胎宽度的平均值（2）轮胎的宽度在[194,196]内，则称这个轮胎是标准轮胎（i）若从甲厂提供的10个轮胎中随机选取1个，求所选的轮胎是标准轮胎的概率？（ii）试比较甲、乙两厂分别提供的10个轮胎中所有标准轮胎宽度的方差的大小，根据两厂的标准轮胎宽度的平均水平及其波动情况，判断这两个工厂哪个厂的轮胎相对更好？【参考答案】***试卷处理标记，请不要删除一、选择题1．B解析：B【解析】分析：由题意逐一考查所给的说法是否正确即可.详解：逐一考查所给的说法：①由分层抽样的概念可知，取东部地区学生2400100240016001000⨯=++48人、中部地区学生1600100240016001000⨯=++32人、西部地区学生1000100240016001000⨯=++20人，题中的说法正确；②新生的人数较多，不适合用简单随机抽样的方法抽取人数，题中的说法错误； ③西部地区学生小刘被选中的概率为100124001600100050=++，题中的说法正确；④中部地区学生小张被选中的概率为100124001600100050=++，题中的说法错误；综上可得，正确的说法是①③. 本题选择B 选项.点睛：本题主要考查分层抽样的概念，简单随机抽样的特征，古典概型概率公式等知识，意在考查学生的转化能力和计算求解能力.2．B解析：B 【分析】根据分层抽样列比例式，解得结果. 【详解】根据分层抽样得应从丙种型号的产品中抽取30060=18200+400+300+100⨯，选B.【点睛】在分层抽样的过程中，为了保证每个个体被抽到的可能性是相同的，这就要求各层所抽取的个体数与该层所包含的个体数之比等于样本容量与总体的个体数之比，即n i ∶N i ＝n ∶N .3．A解析：A 【分析】根据频率分布直方图，分别求得[)4.3,4.4，[)4.4,4.5，[)4.5,4.6，[)4.6,4.7，进而求得[)4.7,5.2的频率，在结合等差数列，求得d ，求得[)4.7,4.8，[)4.8,4.9，[)4.9,5.0，[)5.0,5.1，[)5.1,5.2，进而求得,a b 的值，即可求解.【详解】这100名同学视力的频率分布直方图，其中前4组的频率成等比数列，因为[)4.3,4.4的频率为0.10.10.01⨯=；[)4.4,4.5的频率为0.30.10.03⨯=； [)4.5,4.6的频率为0.0330.09⨯=； [)4.6,4.7的频率为0.0930.27⨯=；[)4.7,5.2的频率为10.010.030.090.270.6----=，所以后6中的频数成等差数列，所以1610.276560.60.272a S a d =⎧⎪⎨⨯=+=+⎪⎩，解得0.05d =-，所以[)4.7,4.8的频率为0.22，[)4.8,4.9的频率为0.17，[)4.9,5.0的频率为0.12，[)5.0,5.1的频率为0.07，[)5.1,5.2的频率为0.02，所以[)4.6,5.0的频率为0.270.220.170.120.78+++=，所以0.27a =，在4.6到5.0之间的数据个数为0.7810078b =⨯=. 故选：A. 【点睛】本题主要考查了频率分布直方图的频率、频数的求法，以及等差数列、等比数列的性质等基础知识的应用，着重考查了运算与求解能力，属于基础题.4．D解析：D 【分析】先根据甲得分的折线图确定被墨迹污损的两个数字取值范围，再根据极差、平均数、中位数等概念以及茎叶图判断大小以及稳定性,即可作出判断选择. 【详解】由茎叶图得乙运动员得分的中位数是17，平均值为9+14+15+17+18+19+20=148根据甲得分的折线图确定被墨迹污损的两个数字取值范围为[13,15]，所以甲运动员得分的极差是28919-=，甲运动员得分有41=82的叶集中在茎1上，甲运动员得分数据比乙分散，所以甲发挥的稳定性比乙运动员发挥的稳定性差，甲运动员得分平均值9+12+13+13+13+20+26+28>>148x 甲，所以D 错误，故选：D 【点睛】本题考查茎叶图、折线图及其应用，考查基本分析判断计算能力，属基础题.5．D解析：D 【分析】根据茎叶图分别找出中位数，求出平均数，方差，即可判断. 【详解】由茎叶图可得：甲组选手得分的平均数：x 甲7582838793845++++==，乙组选手得分的平均数：x 乙7783858591845++++==，两个平均数相等，所以A 选项错误；甲组选手得分的中位数为83，乙组选手得分的中位数为84，所以B 、C 错误；甲组选手得分的方差：2s 甲()()()()()()2222212167584828483848784938455=⨯-+-+-+-+-=，乙组选手得分的方差：2s 乙()()()()()()222221100778483848484858491842055=⨯-+-+-+-+-==，所以甲组选手得分的方差大于乙组选手的的方差. 故选：D 【点睛】此题考查根据茎叶图的数字特征，求平均数，中位数，方差.6．B解析：B 【解析】【分析】应用平均数计算方法，设出两个平均数表达式，相减，即可。

统计学期末考试试卷A-英文版

财经大学07－08第一学期期末考试试卷试卷代码：12083A 授课课时：48课程名称：统计学适用对象：挂牌试卷命题人试卷审核人Ⅰ、SINGLE CHOICE (1′×10＝10′)1、The variable in statistic is( )A quality indexB the concrete expression of the quality indexC variable quantity indexD the concrete expression and index value of the quantity index2、We know the price of a good is 25yuan,the good’s price in here is ( )A indexB variableC quality indexD quality index3 Which of the following statistics indexes is quality index ( )A national incomeB profit rate of capitalC industrial added valueD the national population4、When the range is given, the width of the classes and the number of classes ( )A In Negative proportionB in Positive proportionC DisproportionateD can not judge5、If every value of indexes averaged added 5 units, what will happen about the arithmetical mean? ( )A adds 5 units alsoB only the simple arithmetical mean adds 5 unitsC Reduces 5 unitsD unchanged6 For continuous variable ( )A only can compile different distance seriesB only can compile single seriesC only can compile classinterval seriesD can compile classinterval series ，also can compile single series7、In which situation the mean\mode and median is equals to each other( ) A bell -shaped distribution B U - shaped distributionC bell -shaped distribution or U - shaped distributionD symmetric bell -shaped distribution8、When we infer the population rate and determine the size of sample, if we have the data of population variances in some periods, what should we do about these variances?( )A choose the smallest oneB Choose the largest oneC choose the middle oneD calculate the mean of them 9、A the population mean is a variableB the sample mean is a variableC the population mean and sample mean are variablesD the population mean and sample mean are constants10、In sampling with replacement, what will happen to the sample size if sampling average error decreases 30%? ( )A expands to 2)%301(times of the originalB expands to 2%)30( times of the original C expands to 2%)70( times of the originalD expands to 2)%701(times of the originalⅡ、JUDGE (Write “T” for true and “F” for false. 1′×10＝10′)1、The homogeneity of population is each unit of the population has a same quality index or a same quantity index. ( )2、The absolute value of weight is larger, the effect of it on the arithmetical mean is larger. ( )3、The median 、mode and harmonic mean are not affected by the extreme values. ( )4、statistical classification is according to index. ( )5、Classification according to one index is simple classification, and according to several indexes is multiple classification. ( )6、The standard time in census is the time when the survey data belong to. ( )7、The sample size is in positive proportion to the confidence coefficient, and in positive proportion to the margin of error. ( )8、The production of sampling error is results in destroying the random principle in sample. ( )9、Index and relative number are two different notions; we should not think that they are equal to each other. ( )10、同度量因素在综合指数中既起同度量因素，也起权数作用。

统计学期末考试试卷B-英文版

财经大学07－08第一学期期末考试试卷试卷代码：12083B 授课课时：48课程名称：统计学适用对象：挂牌试卷命题人试卷审核人Ⅰ、SINGLE CHOICE (1′×10＝10′)1、Which statistics is usually used when we compare the deviation degree of twogroups data with different mean?( )A rangeB average deviationC standard deviationD coefficient of variation2、Which of the following average targets is not affected by the extreme values? ()A、Arithmetical meanB、Geometric meanC、Harmonic meanD、Median3、Compare stratified sampling and other sampling methods, when the sample size isequal, the sampling error of stratified is ( )A largerB smallerC be equalD reverse4、The consume price index reflects ( )A the changing tendency and level of the commodity retail priceB the changing tendency and level of the price of inhabitant purchase the consumegoodsC the changing tendency and level of the price inhabitant purchase service itemD the changing tendency and level of the price inhabitant purchase the consumegoods and service item5、In parameter estimate, we must estimate the population parameter by the sample,one of the standard evaluate the statistics is the deviation is smaller is better, this standard is( )A Without biasB EffectivenessC ConsistencyD Adequacy6、In the regression modelεββ++=x y 10，ε reflects ( )A the linear change of y caused by the change of xB the linear change of x caused by the change of yC the effect of random factors to y except the linear relation of x and yD the effect of the linear relation of x and y7、Simple sampling n=50 randomly from a population which the mean is 100, the standard deviation is 10, the expectation and variance of the sample’s mean are( ) A 100 and 0.2 B 100 and 2 C 10 and 1.4 D 10 and 28、The estimate value of the slope of the regression line is 1.23, and the center of the samples is (4, 5), the equation of the regression line is ( )A Yˆ =1.23x ＋4 B Yˆ =1.23x+5 C Yˆ =1.23x+0.08 D Yˆ =0.08x+1.239、What is the year ′s average increasing rate when the increasing rates of recent three years were 7%、9%、11%?( )A. 9%B. 8.8493%C. 8.9878%D. 10% 10、There are three block products, the percent of wastes just as 1.5% 、2% 、1%,the respective quantities of wastes are 25、30 and 45 pieces. Then what is the average rate of waste.( )A 1.5%2%1%3++BC1.5%⨯25+2%⨯30+1%⨯4525+30+45D2530452530451.5%2%1%++++Ⅱ、JUDGE (Write “T” for true and “F” for false. 1′×10＝10′)1、Range is equal to width of the classes multiply the number of classes at any statistical classification. ( )2、Margin of error is generally larger than the standard error of the sampling statistics.( )3、The formula of Paasche index weight for each item is its base-period quantity. ( )4、Correlative coefficient is zero implies that there is no Correlation relationshipbetween variables. ( )5、Whether it is analysis of correlation or analysis of regression, we must determineindependent variable and dependent variable. ( )6、Enlarge the difference between groups and narrow difference within groups is thecommon tenet which is complied at any statistical classification. ( )7、The distribution of population by age is a J –shaped distribution. ( )8、Index and relative number are two different notions; We should not think that theyare equal to each other. ( )9、In 2006, the same amount of RMB in a city can only buy 94% of goods comparedwith 2005, then the price increased by 6% ( )10、Weighted average index is the weighted mean of individual index. ( )Ⅲ、SIMPLE ANSWER（5′×2=10′）1、Briefly describe the differences between cross-sectional and time series data.2、Please list the average targets you have learned.Ⅳ、CALCULATION（15′×3=45′）1、Sample 10 adults and 10 children randomly by replacement sampling, survey the(1) If we want to compare the difference of height between the adult group and children group, which survey index should be chose, why?(2) Analyze which group’s disparity is larger adopt calculate.(3) Assume the height of adult obey normal distribution; provide a 95% confidence interval for the average height of adult.2、A magazine subjected in entertainment claims that 80% of its readers are female. In order to test and verify whether this wording is right, news publish manage branch sampled 200 people randomly from the readers and found that 146 women often read this magazine. At a 0.05 level of significance, do the sample data indicate that the proportion of women reader is 80%? In interval estimate, how many samples must we sample if we want the margin of error decreases to 40% of original? (15’)3、Please compile the quantity index、price index and total change index of three products according to the following data, and then analyze the change in the value of output use the index system.(15’)ⅴ、CASE PROBLEM（25′）A survey of the results of passengers complaining the Civil AviationAs economy developing, people choose take plain more and more. But the attendant problem is passengers complained the airlines more frequently. This phenomenon caused a high degree attention of the manage department. So the manage department sampled 10 airlines randomly and conducted this survey. After this survey, we find out the number of complaints is relates to the percentage of flights arriving on time. The data are given as follows:(1) Develop a scatter diagram for these data, and illustrate the relationship between the two variables.(2) Develop the estimated regression equation use the percentage as dependent variable and the number of complaints as independent variable, and explain the meaning of the regression coefficient.(3) What is the estimated number of complaints if the percentage of flights arriving on times is 80%?(4) Briefly describe the relation between correlation analysis and regression analysis.。

哈佛大学统计学研究生课程考试题pracexam2

Midterm Exam IMath361Name:9/27/10Read all of the following information before starting the exam:•READ EACH OF THE PROBLEMS OF THE EXAM CAREFULLY!•Show all work,clearly and in order,if you want to get full credit.I reserve the right to take oﬀpoints if I cannot see how you arrived at your answer(even if yourﬁnal answer is correct).•A single81/2×11sheet of notes(double sided)is allowed.Calculators are permitted.•Circle or otherwise indicate yourﬁnal answers.•Please keep your written answers clear,concise and to the point.•This test has.problems and is worth100points.It is your responsibility to make sure that you have all of the pages!•Turn oﬀcellphones,etc.•READ EACH OF THE PROBLEMS OF THE EXAM CAREFULLY!•Good luck!123451.(20points)A coin isﬂipped until there are two heads in a row,or three tails.Find the probability that the three tails comesﬁrst.2.(20points)Three integers are chosen with replacement from theﬁrst twenty integers.Find the probability that a.(10pts)Their sum is evenb.(10pts)Their product is even.3.(20points)X is a continuous random variable with cdf F X(x)=1−(1−x)2for0≤x≤1, with F X(x)=0for x≤0,and F X(x)=1for x≥1. a.(10pts)Find the pdf of X.b.(10pts)Let Y=2(X+1)2.Find the cdf of Y.4.(20points)A random integer N from1to10is chosen uniformly at random.a.(10pts)The random variable X denotes the number of distinct prime factors of N. (So if N=8=23,X=1).Find the pmf of X.b.(10pts)Another random integer N from1to10is also chosen uniformly at random. Find the probability that N>2N .5.(20points)Is it possible for two events A and B with P(A),P(B)>0to be both mutually exclusive and independent.Why or why not?Scrap Page(please do not remove this page from the test packet)。

【VIP专享】上外贤达学院概率论与数理统计第一学期(英文版)试卷

3.(15%)A machine produces defective parts with three different probabilities
6.培养学生观察、思考、对比及分析综合的能力。过程与方法1.通过观察蚯蚓教的学实难验点，线培形养动观物察和能环力节和动实物验的能主力要；特2.征通。过教对学观方察法到与的教现学象手分段析观与察讨法论、，实对验线法形、动分物组和讨环论节法动教特学征准的备概多括媒，体继课续件培、养活分蚯析蚓、、归硬纳纸、板综、合平的面思玻维璃能、力镊。子情、感烧态杯度、价水值教观1.和通过学理解的蛔1.虫过1观适、察于3程.观六阅蛔寄内列察、读虫生出蚯让材标容生3根.常蚓学料本教活 2据了见身生：，师的、问解的体巩总鸟看活形用作题蛔线的固结类雌动态手业自虫形练本与雄学、三4摸：学对动状习节人蛔生结、、一收后人物和同课类虫活构请一蚯摸集回体并颜步重关的动、学、蚓蚯鸟答的归色学点系形教生生让在蚓类问危纳。习并从状学理列学平的题害线蚯四线归人、意特出四面体生以形蚓、形纳类大图点常、五观玻表存及动的鸟请动本文小引以见3引、察璃，现预物身类学物节明有言及的、导巩蚯上是状防的体之生和课历什根蚯环怎学固蚓和干，感主是所列环学史么据蚓节二样生练引牛燥鸟染要否以举节到揭不上适动、区回习导皮还类的特分分蚯动的晓同节于物让分答。学纸是减方征节布蚓物一起，课穴并?学蚯课生上湿少法。广的教些，体所居归4在生蚓前回运润的；.泛益鸟色学生纳4靠物完的问答动的原.蛔，处目类和习活环近在成前题蚯的？因了虫以。标生就体的节身其实端并蚓快触及解寄上知物同表内特动体结验和总利的慢摸我蚯生适识学人有容点物前构并后结用生一蚯国蚓在于与的类什，的端中思端线问活样蚓的人? 飞技基有么引进主的的考形题环吗十生体能本着特出行要几变以动1境？节大活，的.方密征本“特节化下物让并为近珍习会形理法切。课生征有以问的2小学什腹稀性引态解。的.课物。什游题主结生出么面鸟和起结蛔关观题体么戏：要利明蚯？处类适哪构虫系察：的特的特用确蚓，等于些特适。蛔章形殊形征板，这是资穴疾点于可虫我态结式。书生种光料居病寄是的们结构，五小物典滑，生？重生鸟内学构5，学、结的型还以活.要生类部习与其习巩鸟结是爱的如原活生结了功颜消固类构线粗鸟形何因的存构腔能色化练适特形糙护态预之结的，肠相是系习于点动？鸟、防一构现你动适否统。飞都物为结蛔。和状认物应与的行是。主构虫课生却为和”其结的与题、病本理不蛔扁的他构8特环以生？8特乐虫形观部特征境小理三页观的动点位点梳相组等、这；，哪物教相，2理适为方引.鸟些，育同师知应单面导鸟掌类结了；？生2识位的学你握日构解.互。办特生认线益特了通动手征观识形减点它过，抄；察吗动少是们理5生报.蛔？物，与的解参一了虫它和有寄主蛔与份解结们环些生要虫其。蚯构都节已生特对中爱蚓。会动经活征人培鸟与飞物灭相。类养护人吗的绝适这造兴鸟类？主或应节成趣的为要濒课的情关什特临？就危感系么征灭来害教；？；绝学，育，习使。我比学们它生可们理以更解做高养些等成什的良么两好。类卫动生物习。惯根的据重学要生意回义答；3的.情通况过，了给解出蚯课蚓课与题人。类回的答关：系线，形进动行物生和命环科节学动价环值节观动的物教一育、。根教据学蛔重虫点1病.引蛔出虫蛔适虫于这寄种生典生型活的线结形构动和物生。理二特、点设；2置.问蚯题蚓让的学生生活思习考性预和习适。于穴居生活的形态、结构、生理等方面的特征；3.线形动物和环节动物的主要特征。

统计学英文版

统计学英文版Part1GatheringandExploring Data (descriptive statistics)Different Types of Data (2.1) VariableA variable is any characteristic observed on the subjects in a study. Examples: Marital status, Height, Weight, IQ, Sqft, Price, NE.A variable can be classified as eitherCategorical (in Categories), orQuantitative (Numerical)A variable can be classified as categorical if each observation belongs to one of a set of categories:Examples:Gender (Male or Female)Religious Affiliation (Catholic, Jewish, …)Type of Residence (Apartment, Condo, …)Belief in Life After Death (Yes or No)NE (Located in northeast sector of city (1) or not (0) )A variable is called quantitative if observations on it take numerical values that represent different magnitudes of the variable. Examples:Age, Number of Siblings, Annual Income, Selling price, Sqft Discrete versus continuous quantitative variablesA quantitative variable is discrete if its possible values form a set ofseparate numbers, such as 0,1,2,3,…The set of possible values is not denseExamples:o Number of pets in a householdo Number of children in a familyo Number of foreign languages spoken by an individualA quantitative variable is continuous if its possible values form anintervalThe set of possible values is denseExamples:o Height/Weighto Ageo Blood pressureExerciseIdentify the variable type1.Number of siblings in a family2.County of residence3.Distance (in miles) of commute to school4.Marital status5.Length of time to take a test6.Number of people waiting in line7.Number of speeding tickets received last year8.Your dog’s weightProportion & Percentage (Relative Frequencies)The proportion of the observations that fall in a certain category is the frequency (count) of observations in that category divided by the total number of observations Frequency of that categorySum of all frequenciesThe percentage is the proportion multiplied by 100Proportions and percentages are also called relative frequenciesExampleTable classifies the 630 parliamentary seats of the Italian chamber of deputies by coalition (2013 elections).Coalition SeatsFreq. Prop. Perc.Pierluigi Bersani 345 0.548 54.8Silvio Berlusconi 125 0.198 19.8Beppe Grillo 109 0.173 17.3Mario Monti 47 0.075 7.46Vallee d'Aoste 1 0.002 0.16MAIAE 2 0.003 0.32USEI 1 0.002 0.16Antonio Ingroia 0 0 0Total 630 1 100so, for Grillo,345 is the frequency.0.548 = 345/630 is the proportion and relative frequency.54.8 is the percentage 0.548×100 = 54.8%.Frequency TableA frequency table is a listing of possible values for a variable, together with the number of observations and/or relative frequencies for each value.Raw data Frequency tableCode Gender Gender n i f i p i000001 F F 1000 0.01 1000002 M M 99000 0.99 99 ... ...100000 FExampleA stock broker has been following different stocks over the last month and has recorded whether a stock is up, the same, or down in value. The results were:1.Performance of stock Up Same DownCount 21 7 12What are the subjects?What is the variable of interest?What type of variable is it?Add proportions to this frequency table.Describe data using graphical summaries (2.2) DistributionA graph or frequency table describes a distribution.A distribution tells us the possible values/categories a variable takesas well as the occurrence of those values (frequency or relativefrequency or percentage)In the 2008 General Social Survey, 2020 respondents answered the question, "How many children have you ever had?" The results wereGraphs for categorical data: bar graphs and pie charts Use pie charts and bar graphs to summarize categorical variables: Pie Chart.o A circle where each category is represented as a “slice of the pie”o The size of each pie slice is proportional to the percentage ofobservations falling in that categoryBar Graph.o Bar Graphs display a vertical bar for each categoryo The height of each bar represents either counts (“frequencies”) or percentages (“relative frequencies”) for that categoryPie Chart52%18%17%13%Cars soldFIAT FORD OPEL RENAULTBar GraphBar graph: easier to compare categoriesBar graphs are called Pareto Charts when the categories are ordered by their frequency, from the tallest bar to the shortest barGraphs for quantitative data: dot plotShows a dot for each subject (observation) placed above its value on a number line. To construct a dot plotDraw a horizontal line and label it with the name of the variable. ?Mark regular values of the variable on it.For each observation, place a dot above its value on the number line.Graphs for quantitative data: histogramsA Histogram is a graph that uses bars to portray the frequencies or the relative frequencies of the possible outcomes for a quantitative variable Steps for constructing a histogram1.Divide the range of the data into intervals of equal width2.Count the number of observations in each interval, creating afrequency table3.On the horizontal axis, label the values or the endpoints of theintervals.4.Draw a bar over each value or interval with height equal to itsfrequency (or proportion or percentage), values of which are marked on the vertical axis.bel and title appropriatelyDisplaying Data over Time: time plotsUsed for displaying a time series, a data set collected over time.Plots each observation on the vertical scale against the time it was measured on the horizontal scale. Points are usually connected.Common patterns in the data over time, known as trends, should be noted.Measuring the Center of Quantitative Data (2.3)。

概率论与数理统计试题（英文）09.1.8

概率论与数理统计试题（英⽂）09.1.82008~2009 第⼀学期《概率论与数理统计（Probability and Statistics ）》考试试卷（A 卷）（闭卷）Name Student I D Class Date: Jan 8, 2009 Time: 8:30 am to 11:00 amQuestion 1 (21 points) Filling the blanks (1). Let A , B be two events, P (A ) = 0.4，P (B ) = 0.3，P (B A ) = 0.6，then P (B ) = .(2). Suppose a random variable X has the probability distribution with20120.30.10.20.4-?? ???, then 2(1)P X ≥= . (3). Suppose ),(Y X has the joint density function<+>>=elsewherey x y x y x f ,01,0,0,2),(, then the marginal distribution for X alone )(x g = .(4). Suppose ),(~2σµN X ，consider a quadratic equation with one unknown220y y X ++= about y , if the probability of this equation having no real root is21, then µ= .(5). The number of distinct permutations can be made from the letters of the wordaccess = .∑==ni i X n X 11 , then =)(2X E . (7). Let n X X X ,,21 be a random sample of size n taken from population2(,)N µσ,µand 2σare unknown ,if 22[(),()]X k X k αα is a confidence interval for µ with confidence level α-1, then k = .(1). Suppose )1,0(~N X , )1,1(~N Y , if X and Y are independent, then ( )(A)2/1)0(=≤+Y X P(B) 2/1)1(=≤+Y X P (C) 2/1)0(=≤-Y X P (D) 2/1)1(=≤-Y X P(2). Suppose X ~ N ( 3, 4 )，Y ~ E ( 5 ) , find the error result ( )(A) ()8E X Y += (B) ()29D X Y +=(C) ()2263E X Y += (D) 50252X Y E ??+-=(3). Suppose that random variables X and Y are independent, if they have the sameprobability distribution with ???? ?3/23/121, then ==)(Y X P ( ) (A) 2/3 (B) 1 (C) 1/2 (D) 5/9(4). Suppose ),(~211σµN X , and ),(~222σµN Y , if 12(1)(1)P X P Y µµ-<>-<,then ( )(A) σ1<σ2(B) σ1>σ2 (C) µ1<µ2 (D) µ1>µ2Question 2 (18 points) Choosing the only one right result2(,)N µσ,∑=--=n i i X X n S 1221)(11，∑=-=n i i X X n S 1222)(1，∑=--=n i i X n S 1223)(11µ，∑=-=ni i X n S 1224)(1µ, then the following random variables which one is the t -distribution with n -1 degrees of freedom. ( ) (A) 11--n S X µ (B) 12--n S X µ (C) n S X 3µ- (D) n S X 4µ- (6). Suppose )(~λP X , 52+=X Y , then XY ρ= ( )(A) 1 (B) -1 (C) 1/2 (D) 0Suppose a random variable X has the density function ?<<=elsewhere x x x f ,010,2)(. Observe X independently for three times, let Y denote the number of an event }{21≤X occurring in three times, determine: (1) the probability distribution of Y ;(2) the probability distribution of 2Y .Question 3: (12 points)Suppose ),(Y X has the joint density function as follows:≤≤≤≤+=elsewhere y x y x c y x f 010,10)(),(2 . (1)Find the constant c ;(2) Are X and Y independent?(3) Determine the conditional distribution of X for any given value of Y . (4)11()22P X Y <=Question 4 (14 points)Suppose that a box contains one fair coin and one coin with a head on each side. Suppose also that one coin is selected at random and tossed, a head is obtained. Determine:(1) the probability of this event occurring ;(2) the probability that this coin is the fair coin when the above event occurred.Question 5 (10 points)There are 4 girls and 8 boys take part in interview of some company. Suppose that the interviewer select one student randomly every time, determine the probability that there are just 2 boys waiting for interviewing when all the girls have interviewed.Question 6 (5 points)Suppose a random variable X has the density function ??≤<-≤<-+=elsewhere x x x x x f 010,101,1)( ,let0,01,0X Y X0,1,X Z Xdetermine:(1) the joint probability distribution of (Y , Z ) ;(2) D(Y +Z ).Question 7 (12 points)Suppose a population has the density function <≥=--θθθx x e x f x ,0,3)()(3 , where θ is unknown parameter. Let n X X X ,,21 be a random sample of size n taken from population, find the maximum likelihood estimator for θ.Question 8 (8 points)。

《统计学基础(英文版·第7版)》题库答案les7e_ptb_01

Chapter 1Introduction to Statistics1.1An Overview of Statistics1Distinguish Between a Population and a SampleMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Determine whether the data set is a population or a sample.1)The age of every fourth person entering a department storeA)sample B)population2)The age of each employee at a local grocery storeA)population B)sampleSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Identify the population and the sample.3)A survey of 1212 American households found that 52% of the households own a computer.4)When 1348 American households were surveyed, it was found that 57% of them owned two cars.5)A survey of 2625 elementary school children found that 28% of the children could be classified as obese. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.Use the Venn diagram to identify the population and the sample.6)A)Population: Magazine subscribers; Sample; Magazine subscribers who renew their subscriptionB)Population: Magazine subscribers who renew their subscription; Sample: Magazine subscribers2Distinguish Between a Parameter and a StatisticSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Determine whether the numerical value is a parameter or a statistic. Explain your reasoning.7)A recent survey by the alumni of a major university indicated that the average salary of 10,500 of its 200,000graduates was $130,000.8)The average salary of all assembly-line employees at a certain car manufacturer is $44,000.9)A survey of 1040 students was taken from a university with 19,000students.3Distinguish Between Descriptive Statistics and Inferential StatisticsMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Identify whether the statement describes inferential statistics or descriptive statistics.10)The average age of the students in a statistics class is 20years.A)descriptive statistics B)inferential statistics11)The chances of winning the California Lottery are one chance in twenty-two million.A)inferential statistics B)descriptive statistics12)There is a relationship between smoking cigarettes and getting emphysema.A)inferential statistics B)descriptive statistics13)From past figures, it is predicted that 31% of the registered voters in California will vote in the June primary.A)inferential statistics B)descriptive statistics14)Based on previous clients, a marriage counselor concludes that the majority of marriages that begin withcohabitation before marriage will result in divorce.A)inferential statistics B)descriptive statistics4ConceptsSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Provide an appropriate response.15)Explain the difference between a sample and a population.16)If you had to do a statistical study, would you use a sample or a population? Why?1.2Data Classification1Distinguish Between Qualitative and Quantitative DataMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Determine whether the data are qualitative or quantitative.1)the colors of automobiles on a used car lotA)qualitative B)quantitative2) the number of complaint letters received by the United States Postal Service in a given dayA)quantitative B)qualitative3)the number of seats in a movie theaterA)quantitative B)qualitative4)the numbers on the shirts of a girlʹs soccer teamA)qualitative B)quantitative2Classify Data with Respect to the Four Levels of MeasurementMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Identify the data setʹs level of measurement.5)hair color of women on a high school tennis teamA)nominal B)ordinal C)interval D)ratio6)numbers on the shirts of a girlʹs soccer teamA)nominal B)ordinal C)interval D)ratio7)ages of students in a statistic classA)ratio B)ordinal C)interval D)nominal8)temperatures of 26 selected refrigeratorsA)interval B)ordinal C)nominal D)ratio9)number of milligrams of tar in 30 cigarettesA)ratio B)ordinal C)interval D)nominal10)number of pages in your statistics bookA)ratio B)ordinal C)interval D)nominal11)marriage status (married, single, or divorced) of the faculty at the University of ColoradoA)nominal B)ordinal C)interval D)ratio12)list of 1240 social security numbersA)nominal B)ordinal C)interval D)ratio13)the ratings of a movie ranging from ʺpoorʺ to ʺgoodʺ to ʺexcellentʺA)ordinal B)nominal C)interval D)ratio14)the final grades (A, B, C, D, and F) for students in a statistics classA)ordinal B)nominal C)interval D)ratio15)the annual salaries for all teachers in CaliforniaA)ratio B)ordinal C)interval D)nominal16)list of zip codes for ChicagoA)nominal B)ordinal C)interval D)ratio17)the nationalities listed in a recent survey (for example, Asian, European, or Hispanic).A)nominal B)ordinal C)interval D)ratio18)the amounts of fat (in grams) in 37 cookiesA)ratio B)ordinal C)interval D)nominal19)the years the summer Olympics were held in the United StatesA)interval B)ordinal C)nominal D)ratio20)numbers of touchdowns scored by a major university in five randomly selected games53134A)ratio B)ordinal C)interval D)nominal21)the average daily temperatures (in degrees Fahrenheit) on five randomly selected days2123213027A)interval B)nominal C)ordinal D)ratio22)manuscripts rated ʺacceptableʺ or ʺunacceptableʺA)ordinal B)nominal C)ratio D)interval23)the lengths (in minutes) of the top ten movies with respect to ticket sales in 2007A)ratio B)nominal C)ordinal D)interval24)the data listed on the horizontal axis in the graphA)nominal B)interval C)ordinal D)ratio25)the data listed on the horizontal axis in the graphA)ratio B)nominal C)ordinal D)interval3ConceptsSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Provide an appropriate response.26)Explain the differences between the interval and ratio levels of measurement.27)Explain why data expressed with the Celsius temperature scale is at the interval level of measurement ratherthan the ratio level.1.3Data Collection and Experimental Design1Decide Whether Study is Observational Study or ExperimentMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.Determine whether the study is an observational study or an experiment.1)A medical researcher obtains a sample of adults suffering from diabetes. She randomly assigns 89people to atreatment group and 89 to a placebo group. The treatment group receives a medication over a period of threemonths and the placebo group receives a placebo over the same time frame. At the end of three months thepatientsʹ symptoms are evaluated.A)experiment B)observational study2)A poll is conducted in which professional musicians are asked their ages.A)observational study B)experiment3)A pollster obtains a sample of students and asks them how they will vote on an upcoming referendum.A)observational study B)experiment4)The personnel director at a large company would like to determine whether the company cafeteria is widelyused by employees. She calls each employee and asks them whether they usually bring their own lunch, eat at the company cafeteria, or go out for lunch.A)observational study B)experiment5)A scientist was studying the effects of a new fertilizer on crop yield. She randomly assigned half of the plots ona farm to group one and the remaining plots to group two. On the plots in group one, the new fertilizer wasused for a year. On the plots in group two, the old fertilizer was used. At the end of the year the average cropyield for the plots in group one was compared with the average crop yield for the plots in group two.A)experiment B)observational study6)A researcher obtained a random sample of 100 smokers and a random sample of 100 nonsmokers. Afterinterviewing all 200 participants in the study, the researcher compared the rate of depression among thesmokers with the rate of depression among nonsmokers.A)observational study B)experimentSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Identify the experimental units and treatments used in the experiment.7)A medical researcher center wants to test the effectiveness of a new diabetes medication. The companyidentifies 98 adults suffering from a similar form of diabetes. The subjects are randomly assigned to twogroups. One group is given a medication and the other is given a placebo that looks exactly like the medication.After three months, the subjectsʹ symptoms are studied and compared.2Identify a Biased SampleSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Provide an appropriate response.8)Explain what bias there is in a study done entirely online.9)A report sponsored by the California Citrus Commission stated that cholesterol levels can be lowered bydrinking at least one glass of a citrus product each day. Determine if the report is biased.10)A local newspaper ran a survey by asking, ʺDo you support the deployment of a weapon that could killmillions of innocent people?ʺ Determine whether the survey question is biased.3Identify Sampling TechniquesMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.Identify the sampling technique used.11)Thirty-five sophomores, 30 juniors and 33seniors are randomly selected from 281 sophomores, 242juniors and529 seniors at a certain high school.A)stratified B)random C)cluster D)convenience E)systematic12)Every fifth person boarding a plane is searched thoroughly.A)systematic B)random C)cluster D)convenience E)stratified13)At a local community college, five statistics classes are randomly selected out of 20 and all of the students fromeach class are interviewed.A)cluster B)random C)convenience D)systematic E)stratified14)A researcher randomly selects and interviews fifty male and fifty female teachers.A)stratified B)random C)cluster D)convenience E)systematic15)A researcher for an airline interviews all of the passengers on five randomly selected flights.A)cluster B)random C)convenience D)systematic E)stratified16)A community college student interviews everyone in a particular statistics class to determine the percentage ofstudents that own a car.A)convenience B)random C)cluster D)systematic E)stratified17)Based on 12,500 responses from 36,500questionnaires sent to its alumni, a major university estimated that theannual salary of its alumni was $116,000 per year.A)random B)stratified C)cluster D)convenience E)systematic18)In a recent television survey, participants were asked to answer ʺyesʺ or ʺnoʺ to the question ʺAre you in favorof the death penalty?ʺ Six thousand five hundred responded ʺyesʺ while 4700 responded ʺnoʺ. There was afifty-cent charge for the call.A)convenience B)random C)cluster D)stratified E)systematic19)A lobbyist for a major airspace firm assigns a number to each legislator and then uses a computer to randomlygenerate ten numbers. The lobbyist contacts the legislators corresponding to these numbers.A)random B)convenience C)cluster D)stratified E)systematic20)To ensure customer satisfaction, every 20th phone call received by customer service will be monitored.A)systematic B)random C)cluster D)stratified E)convenience21)A market researcher randomly selects 400 drivers under 45years of age and 100 drivers over 45years of age.A)stratified B)random C)cluster D)convenience E)systematic22)To avoid working late, the quality control manager inspects the last 60 items produced that day.A)convenience B)random C)cluster D)stratified E)systematic23)The names of 70 contestants are written on 70 cards. The cards are placed in a bag, and three names are pickedfrom the bag.A)random B)stratified C)cluster D)convenience E)systematic24)A researcher randomly selected 70 of the nationʹs middle schools and interviewed all of the teachers at eachschool.A)cluster B)random C)stratified D)convenience E)systematicSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Provide an appropriate response.25)After a hurricane, a disaster area is divided into 200 equal grids. Thirty of the grids are selected and everyoccupied household in the grid is interviewed to help focus relief efforts. Select the numbers of the first fivegrids that belong to the cluster sample.163487693890169513925588771015092097915726)There are 750 incoming freshmen attending a university this fall. A researcher wishes to send questionnaires toa sample of 30 of them to complete regarding their drinking habits. Select the numbers of the first fivefreshmen who belong to the simple random sample.163487693890169513925588771015092097915727)A college employs 85 faculty members. Without replacement, select the numbers of the five members who willserve on the tenure committee next year.163487693890169513925588771015092097915728)Of the 5000 outpatients released from a local hospital in the past year, one hundred were contacted and askedtheir opinion on the care they received. Select the first five patients who belong to the simple random sample.1634876938901695139255887710150920979157MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Determine whether you would take a census or use a sampling. If you would use a sampling, decide what sampling technique you would use.29)The average age of the 80 residents of an assisted living center.A)census B)random sampling C)stratified sampling D)cluster sampling 4ConceptsSHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.Provide an appropriate response.30)Explain the differences between cluster sampling and stratified sampling.31)Explain the difference between a census and a sampling and describe the advantages and disadvantages ofeach.Chapter 1Introduction to StatisticsAnswer Key1.1An Overview of Statistics1Distinguish Between a Population and a Sample1)A2)A3)population: collection of all American households; sample: collection of 1212American households surveyed4)population: collection of all American households; sample: collection of 1348American households surveyed5)population: elementary school children; sample: collection of 2625 elementary school children surveyed.6)A2Distinguish Between a Parameter and a Statistic7)It describes a statistic because the number $130,000is based on a subset of the population.8)It describes a parameter because the $44,000is based on all the workers at the car manufacturer.9)It describes a statistic because the number 1040is based on a subset of the population.3Distinguish Between Descriptive Statistics and Inferential Statistics10)A11)A12)A13)A14)A4Concepts15)A population is the collection of all outcomes, responses, measurements, or counts that are of interest.. A sample is asubset of a population.16)A sample would be used. It is usually impractical to obtain all the population data.1.2Data Classification1Distinguish Between Qualitative and Quantitative Data1)A2)A3)A4)A2Classify Data with Respect to the Four Levels of Measurement5)A6)A7)A8)A9)A10)A11)A12)A13)A14)A15)A16)A17)A18)A19)A20)A21)A22)A23)A24)A25)A3Concepts26)Data at the ratio level are similar to data at the interval level, but with the added property that a zero entry is aninherent zero (implies ʺnoneʺ). Also, for data at the ratio level a ratio of two data values can be formed so that one data value can be expressed as a multiple of another.27)Such data is at the interval level rather than the ratio level because the temperature of 0°C does not represent acondition where no heat is present, so it is not an inherent zero as required by the ratio level. Also, ratios of twotemperatures cannot be formed so that one data value is expressed as a multiple of the other. The temperature 2°C is not twice as warm as 1°C.1.3Data Collection and Experimental Design1Decide Whether Study is Observational Study or Experiment1)A2)A3)A4)A5)A6)A7)The experimental units are the 98 adults in the study. The treatment is the new diabetes medication.2Identify a Biased Sample8)The study may be biased because it is limited to people with computers.9)A report sponsored by the citrus industry is much more likely to reach conclusions favorable to the industry.10)The wording of the question is biased, as it tends to encourage negative responses.3Identify Sampling Techniques11)A12)A13)A14)A15)A16)A17)A18)A19)A20)A21)A22)A23)A24)A25)163, 169, 15, 92, 9726)163, 487, 693, 169, 51327)16, 34, 69, 38, 1328)1634, 3890, 1695, 1392, 150929)A4Concepts30)In stratified sampling, members of the population are divided into two or more subsets, or strata, that share a similarcharacteristic. A sample is then randomly selected from each of the strata. A stratified sample has members from each segment of the population. In cluster sampling, the population is divided into naturally occurring subgroups, each having similar characteristics. All of the members in one or more (but not all) of the clusters are then selected. In a cluster sample, care must be taken to ensure that all clusters have similar characteristics.31)A census is a count or measure of an entire population, while a sampling is a count or measure of part of a population.A census provides complete information but is often expensive, difficult, and time consuming to perform especially ifthe population is large. A sampling is less expensive and time consuming, however appropriate sampling techniques must be used to ensure that unbiased data are collected and that the sample is representative of the population. Even with the best sampling methods, sampling error can occur.。

第一学期八年级英文招生试卷(国际班)

第一学期八年级国际班英文招生试卷姓名原就读学校I. VocabularyA.Fill in the blank with correct adjectives: (15)[ Gorgeous , Scorching , Terrified , Freezing , Furious , Fascinated , Ardous , Exhausted , Essential , Hilarious ]1.When I broke the glass window , my mother was ___________________2.I have been working all day and I feel ____________________3.Roy’s tongue got burnt because of the ________________ coffee.4.Her stylist has bought a _______________ dress for her .5.They said it was not easy to go out in this ________________ weather .6.It is _______________ for us to keep a balanced diet for a healthy body .7.I was quite ________________ by the Harry Potter books and movies .8.My dad has been ________________ of spiders but he tries to be brave in front of others .9.John has a _________________ personality . He is always cracking jokes .10.This paper is _______________ to solve . We will be angry with the teacher .B.Add suitable suffix to make a new word : (5)1.The only _____________ (weak) he has , is that he gets angry quickly.2.I never saw this kind of ____________ ( demonstrate) outside the offices.3.You should drive more ______________ ( care) on a crowded road .4.She is a very ___________ ( fame) TV Star .5.There is no ______________ (inform) about t omorrow’s exam as of now .C.Choose the correct option: (5)1.Tomorrow you have to give/take a test in the English language .2.When we meet you can make/take a break from work .3.My mother wants me to make/have progress in other subjects too.4.I would should/would go to the restaurant if I could.5.It’s not good. We shouldn’t/wouldn’t be happy .II. GrammarD.Write the correct passive form of the sentence : (15)1.Many people begin new projects in January.__________________________________________________________________________ 2.They make shoes in that factory.__________________________________________________________________________ 3.We will examine you again.__________________________________________________________________________ 4.The businessmen will meet the visitors at the airport.__________________________________________________________________________ 5.All workers will read the memo.__________________________________________________________________________E.Correct the following sentences (10)1.The boy which next to me in class is very clever .__________________________________________________________________________ 2.Our neighbor when cat ran away last night is very happy today .__________________________________________________________________________ 3.The school which I studied was destroyed by fire .__________________________________________________________________________ 4.At weekend that family is at home we have breakfast together ._________________________________________________________________________ 5.Apple is the one fruit who I hate the most .__________________________________________________________________________AnswersA.1. furious2.exhausted3.scorching4.gorgeous5.freezing6.essential7. fascinated8.terrified9. hilarious10.arduousB.1. weakness2. demonstration3. carefully4. famous5. informationC.1. take2. take3. make4. would5.shouldn'tD.1. New projects are begun in January.2. Shoes are made in that factory.3. You will be examined again.4. The visitors will be met the businessmen at the airport.5. The memo will be read by all workers.6. that must be done.7. Animals should not be named.8. The other player was defeated.9. I mustn't be questioned.10. Big companies are chosen by many guys.E.1.The boy who sits next to me in class is very clever.2. Our neighbor whose cat ran away last night is very happy today.3. The school where I studied was destoryed by fire.4. At weekend when family is at home we have breakfast together.5. Apple is the one fruit which I hate the most.。

APS+统计、西经、会计英语

统计学Statistics is the study of the collection, organization, analysis, and interpretation of data.1.统计变量集中趋势的测定：To measure the central tendency of statistical variables.Statistical indicators: arithmetic mean (distinguished from the geometric mean or harmonic mean), weighted average, mode, median…2.统计变量离散程度的判定： To measure the dispersion degree of the statistical variables . ['vε?ri?bl]Statistical indicators: range, average deviation(平均差), variance, standard deviationVariance: it is a measure of how far a set of numbers are spread out from each other.Standard deviation: It shows how much variation or "dispersion" there is from the average.3.抽样分布：In statistics, a sampling distribution is the probability distribution of a given statistic based on a random sample.标准误差：Standard error ---The standard deviation of the sampling distribution of the statistic is referred to as the standard error of that quantity.4.参数估计：Parameter estimation is the process that uses the samples from a population to estimate the parameter of the population, such as the population mean, the population variance, etc.5.假设检验：Statistical hypothesis testing is making a hypothesis about the parameter or distribution of a population in advance, then using the sample information to determine whether the hypothesis is reasonable or not.显著性水平：The amount of evidence required to accept that an event is unlikely to have arisen by chance is known as the significance level or critical p-value.Null/Alternate hypothesis: 零假设备择假设计量经济学Econometrics [i, k?n?’metriks] has been defined as "theapplication of mathematics and statistical methods to economic data" and described as the branch of economics "that aims to give empirical[em'pirik?l] content to economic relations."相关分析：Correlation analysis—analyze the relationship between two variables—usually using the correlation coefficient to describe the relationship:R=1 perfect correlationR=0 uncorrelatedR is between 0 and 1: partial correlation回归分析：Regression analysis: linear regression is an approach to modeling the relationship between a scalar variable y and one or more explanatory variables denoted X.Simple regression: one explanatory variableMultiple regression: More than one explanatory variable可决系数在数值上等于简单线性相关系数的平方Coefficient of determination is numerically equal to the square of a simple linear correlation coefficient.多重共线性multicollinearity [,m?ltik?li'ni?riti]：Multicollinearity is a statistical phenomenon in which two or more predictor variables in a multiple regression model are highly correlated.Remedies： Ridge regression；Obtain more data, if possible; Dropone of the variables.异方差性Heteroscedasticity [,het?r?usk?d?s'tis?ti]：if there are sub-populations that have different variabilities than others.Remedies：Weighted least squares自相关Auto correlation：Auto correlation is the phenomenon that there exists correlativity among the random error terms.Remedies: The Generalized Difference Method西方经济学Macroeconomics：Macroeconomics is a branch of economics dealingwith the performance, structure, behavior, and decision-making of the entire economy. This includes a national, regional, or global economy.Measures of national income and output: to estimate total economic activity in a country or region, including gross domestic product (GDP), gross national product (GNP), and net national income (NNI)---The expenditure approach. It focuses on finding the total output of a nation by finding the total amount of money spent.[C = household consumption, I = gross private domestic investment, G = government consumption and gross investment, X = gross exports of goods and services, M = gross imports of goods and services]---The income approach. It equates the total output of a nation to the total factor income received by people of the nation.National income = Compensation of employees + Net interest + Rental & royalty income + Profit of firms + Income from self-employment + NFIA (net factor income from abroad).The IS/LM model (Investment Saving/Liquidity preference Money supply) is a macroeconomic tool that demonstrates the relationship between interest rates and real output in the goods and services market and the money market.。