Tests of significance

合集下载

significance用法(一)

significance用法(一)significanceDefinition and OverviewSignificance refers to the importance or relevance of something. It represents the meaning, impact, or value that something carries or holds. The term is often used to describe the degree of influence or effect that a particular person, event, object, or idea has on a situation or context. Usage Examples and Explanations1.Statistical Significance: In the field ofstatistics, significance is used to determine whether a result is statistically meaningful or simply due tochance. Statistical significance is often measuredthrough hypothesis testing, where the probability ofobtaining the observed result by chance is evaluated. If the probability is below a certain threshold (typically 5% or 1%), the result is considered statisticallysignificant.2.Historical Significance: Historicalsignificance refers to the impact or importance of anevent or individual in shaping history. It involves evaluating the long-term consequences and implications of a specific event, such as a revolution, invention, or discovery. For example, the invention of the printing press by Johannes Gutenberg has significant historical importance due to its transformative effect on communication and knowledge dissemination.3.Cultural Significance: Cultural significance pertains to the importance of certain traditions, customs, or artifacts within a particular culture or society. It signifies the value and meaning attached to these elements and their role in shaping the identity and heritage of a community. For instance, the Chinese New Year holds cultural significance as it symbolizes traditional values, family reunions, and the start of a new lunar year in Chinese culture.4.Personal Significance: Personal significance refers to the individual meaning or significance that someone assigns to a particular event or experience. It represents the emotional, psychological, or personal impact that an event has on an individual’s life. For example, receiving a prestigious award may have personalsignificance for someone as it validates their hard work and achievements.5.Scientific Significance: In scientific research, significance refers to the importance ornovelty of a finding or result. It indicates thepotential impact on the existing body of knowledge orits applicability to practical applications. Ascientific study with significant findings cancontribute to advancements in the field and shape future research directions.6.Symbolic Significance: Symbolic significance pertains to the meaning or representation that a symbol holds within a cultural, religious, or contextual context. Symbols such as national flags, religious icons, or social emblems carry symbolic significance as they represent larger concepts, values, or ideals. For example, the Olympic rings symbolically represent the unity of different continents participating in the Olympic Games.7.Global Significance: Global significancerefers to the impact or importance of an issue, event,or phenomenon on a global scale. It signifies the magnitude of its influence beyond national or regionalboundaries. For instance, climate change has globalsignificance as it affects ecosystems, economies, andhuman well-being worldwide.8.Legal Significance: Legal significance relatesto the importance or implications of a legal principle,precedent, or decision. It represents the authority orweight that a particular legal ruling holds in shapingfuture legal interpretations or judgments. For example,landmark court cases can have legal significance as they establish new legal standards or interpretations. ConclusionSignificance encompasses various aspects of importance, relevance, or impact across different fields and contexts. Whether it is statistical, historical, cultural, personal, scientific, symbolic, global, or legal significance, understanding the degree and meaning of significance helps in comprehending the broader implications and effects of events, ideas, or phenomena.。

of clinical significance

of clinical significance“of clinical significance”这个短语通常用于医疗保健和医学研究的语境中，用来描述具有在临床环境中实际重要性或相关性的发现、结果或观察。

当某事被认为“of clinical significance”时，这意味着它对于患者病情的诊断、治疗或管理具有有意义的影响。

在评估研究结果或医学检测结果的实际影响时，这个概念是至关重要的。

For example:1.Research Findings: In clinical studies, researchers may identify a statistical differencebetween two groups. However, to be considered "of clinical significance," this difference should have a meaningful impact on patient outcomes or healthcare practices.研究结果：在临床研究中，研究人员可能会发现两组之间存在统计学差异。

然而，要被认为是“of clinical significance”，这种差异应该对患者的结果或医疗实践产生有意义的影响。

2.Diagnostic Tests: A diagnostic test may detect a slight variation in a parameter, but it is onlyconsidered "clinically significant" if that variation is relevant to the diagnosis, prognosis, or treatment decisions for the patient.诊断测试：诊断测试可能会检测到某个参数的轻微变化，但只有在这种变化对患者的诊断、预后或治疗决策具有相关性时，才被认为是“of clinical significance”。

Tests of Significance

homework
• 1,2,4,5,6,8,10,13,18.22
ห้องสมุดไป่ตู้
Alternative hypothesis
• It is stated in the form of an inequality, in the other words, we can treat the alternative hypothesis as the doubt we throw against the null hypothesis.
P-value in the test
• In the test, the difference between two hypothesizes can be • (1) the difference from the original sample calculating • (2) the difference occur as they come from the different population • Only situation 2 is the reason we reject the null hypothesis.
Hypothesis test for a difference between two means.
• As the material we obtain are only two independent simple random sample, in most case, we use the t-distribution. • Through the t-value we calculated, we determine the range in which the p-value is located.

金融计量

Chapter 11 Types of Data and Notation• There are 3 types of data which econometricians might use for analysis: 1. Time series data 2. Cross-sectional data （截面数据） 3. Panel data, a combination of 1. & 2.（面板数据）• The data may be quantitative （定量）(e.g. exchange rates, stock prices, number of sharesoutstanding), or qualitative （定性）(e.g. day of the week).• Examples of time series data Series Frequency GNP or unemployment monthly, or quarterly government budget deficit （赤字预算） annually money supply weekly value of a stock market index as transactions occur 2 Returns in Financial Modelling• It is preferable not to work directly with asset （资产） prices, so we usually convert （转变） the raw （未加工的） prices into a series of returns. There are two ways to do this:Simple returns or log returnswhere, Rt denotes the return at time t pt denotes the asset price at time t ln denotes the natural logarithm• We also ignore any dividend （股息） payments, or alternatively assume that the priceseries have been already adjusted to account for them.Log ReturnsThe returns are also known as log price relatives, which will be used throughout this book. There are a number of reasons for this: 1. They have the nice property that they can be interpreted as continuously Compounded （复合） returns. 2. Can add them up, e.g. if we want a weekly return and we have calculated daily log returns: r1 = ln p1/p0 = ln p1 - ln p0 r2 = ln p2/p1 = ln p2 - ln p1 r3 = ln p3/p2 = ln p3 - ln p2 r4 = ln p4/p3 = ln p4 - ln p3 r5 = ln p5/p4 = ln p5 - ln p4 −−−−−ln p5 - ln p0 = ln p5/p0%10011⨯-=--t t t t p p p R %100ln 1⨯⎪⎪⎭⎫ ⎝⎛=-t t t p p RA Disadvantage of using Log Returns• There is a disadvantage of using the log-returns. The simple return on a portfolio （证券投资组合） of assets is a weighted average of the simple returns on the individual assets:• But this does not work for the continuously compounded returns.Chapter 23 回归模型中拟合优度的含义拟合优度（Goodness of Fit ）是指回归直线对观测值的拟合程度。

GradingPeriod

1.2 Displaying Data with Graphs Describe distributions Basic Graphs and interpret data from observed patterns
1.3 Describing Quantitative Data with Numbers Four Measures of Cent er 5 number summary, IQR, Choosing appropriate measure of center
S-ID.2
Possible Assignments p. 22: 9 – 13, 19 – 24 p.42: 39 – 42, 48, 49
p. 70: 81 – 86, 91, 94
Other Relate d Materials Use of Graphs on the TI-84 Use of Data on TI-84
4.1 Sampling and Surveys Population and sample Sampling techniques Coverage and undercoverage Sampling errors and non-response
4.2 Experiments Observational studies Exp eriment s Experimental vocabulary Randomized Design
4.3 Using studies wisely Inference and causation Data Ethics Bias
Common Core Stan da rd(s ) 7-SP.1 S-ID.5 S-CP .4
A-CED.1 A-SSE.1

第六讲方差分析(下)

Error(Animal)
Sphericity Assumed Greenhouse-Geisser Huynh-Feldt Lower-bound
5.5 结果分析与表达
Tests of Within-Subjects Contrasts Measure:
MEASURE_1
Source Animal
5.7
3
5.1 RM基本概念
Repeated measures（RM）是指在实验过程中，相同的实体（entities, e.g. participants）参与所有情况下的（实验控制变量的不同水平下的）实验或者在不同的时间点下提供数据。
其它的表达方式： Within-participants design, Related design, Within-subjects design
8
5.2.2在SPSS中进行球形检验
实际检验方法：在SPSS中球形检验可以通过Mauchly’s test进行。其零假设为：实验不同情况下差异的方差是相等的。若Mauchly’s test的检验结果不显著，则球形检验通过。
9
5.2.3 球形检验没通过怎么办？
当球形检验没通过时： ε >0.75, 采用Huynh–Feldt estimate的结果 ε <0.75或未知，采用Greenhouse– Geisser 修正结果
b b
(I) Animal 1
2 3 4
Lower Bound .925 1.339 -4.141 -6.825 -4.244 -6.359 -6.661 -4.494 -8.249 -8.891 -3.359 -4.999
Upper Bound 6.825 6.661 8.891 -.925 4.494 3.359 -1.339 4.244 4.999 4.141 6.359 8.249

InterimAnalysisofClinicalTrials

“An interim analysis is any assessment of data done during the patient enrollment or follow-up stages of a trial for the purpose of assessing center performance, the quality of the data collected, or treatment effects.”[1] Interim analysis is also called “data-dependent stopping” or “early stopping”. Interim analyses are most often used to find convincing enough evidence to say that there is a significance large treatment difference, and that the difference is convincing enough to chance the trial at a point earlier than planned at first.Ethical and economic reasons are also taken into consideration to stop the trial early.[4] [10] The ethical reason is the most important reason to stop the trial. We want to make sure that the maximum number of patients receives the most effective treatment at the earliest stage. Since clinical trials are expensive, there are also economic reasons to include as few patients as possible.[10]Interim analysis is also used to possibly reduce the expected number of patients and to shorten the follow-up time needed to make a conclusion. [11].You don’t want to spend extra money if you already have enough evidence.Other Examples of Why a Trial May Be Terminated*•Treatments are convincingly different•Treatments are convincingly not different•Unacceptable side effects or toxicity•Accumulation is so slow that trial is no longer sufficient•Outside information surfaces that makes the trial unnecessary or unethical•Poor execution compromises the ability of the study to meet its objectives•Disastrous fraud or misconduct.*[3]Special Statistical ProblemsI.The Multiple Looks ProblemA problem that is often ignored in clinical trials is when an experimenter continuously executes interim analysis over the course of the study. We define this problem as “The Multiple Looks Problem.”[1] [2].When interim analysis is done repetitively the decision to terminate a trial early because of convincing evidence that the treatments are or are not different. The mistake is made when researchers treat each ‘look’ at the analysis as if it was the only one. However, the false-positive rate increases as the number of interim analyses increases. As the data is reviewed more and more, the false positive rate is going to increase because the greater the chance of mistaking a real effect for a large statistical fluctuation increases. For example, if we plan to have our clinical trial to have and alpha of 5%, and we want to conduct 5 interim analyses then the false positive rate would be changed to 14%. [2] So, because we are looking more for a difference in treatments, there is a greater chance that at one of these times we are going to find a statistical instability or what we call a “False-Positive Look.” The table below shows the how the false-positive rate changes with a varying number of false-positive looks at the data with a planned alpha level of .05.Multiple "Looks" at Data versus False-Positive Rate* *Number of “Looks” False-Positive Rate10.0520.0830.1140.1350.1410 0.1920 0.2550 0.321000.3710000.53∞ 1.0*[9]Every time we look at the data and consider stopping, we introduce the chance of falsely rejecting the null hypothesis. In other words, we increase the Type I error. If we look at the data multiple times, and use alpha of 0.05 as our criterion of significance, then we have 5% chance of stopping each time.[3]II.The Multiple Outcomes ProblemThe Multiple Outcome Problem occurs when there are two or more outcome measures that are used to analyze the study treatments. The Multiple Outcome Problem even occurs when the clinical trial, which was planning on focusing on one outcome and the necessity to focus on the other outcome, is necessary.[1] Among the three problems, this one is believed to be the most difficult to address, because the outcomes of interest are likely to be interdependent. “The usual approach is to ignore the interdependence and to make comparisons involving the different outcome measures as if they were independent of one another.”[1] However, unless the conclusions are preceded with extreme caution this can lead to incorrect conclusions.An example from the book had a placebo and a treatment that were applied to a certain heart study, and were measuring death as an outcome. It was found that they didnot reject the null hypothesis that there was a statistical difference between the treatment and the placebo for the outcome “all causes of death.” However, there was a significant difference when the outcome was specified to “Cardiovascular Related Death.” Here the “Cardiovascular Related Death” was a subset of “all causes of death.” There is no real solution to this problem, other than to provide the conclusions and analysis of all outcomes, and subsets of these outcomes.III.The Multiple Comparisons Problem“The multiple comparisons problem arises when an investigator chooses to make several different treatment comparisons all involving the same outcome measure (and all done at the same point.” [1] There are two settings to this. One, is it is of interest to determine if subgroups of the patients are benefited or harmed by the treatment. This analysis is called Data Dredging[1]. One thing that should be noted is that you should avoid conventional interpretation of significance tests. The other, is when the experimenter is interested in more than one treatment either with each other or with the control group. To make a conclusion about one treatment being superior the experimenter must carry out one of the multiple comparison tests.Sequential and Group Sequential MethodsA sequential Method is when the accumulating data are analyzed at every new observation. However, the more times the data is analyzed leads to statistical problems which were talked about it in the Multiple Looks Problem. A Group Sequential Method is when datat is analyzed at pre-determined intervals.•Group sequential tests are convenient, and they also provide plenty opportunity for early stopping.•It achieves lower expected sample size and shorter average study lengths.•Can provide a possible compromise between too long a duration of a trial and too biased results.•It is more practical than standard sequential methods.[8]•At each interim analysis , a comparison of treatments is done and it is decide whether there is sufficient evidence to stop the trial•An “Independent Data Monitoring Committee” is used to review or conduct the interim analysis[7]Study Design with Interim MonitoringA significance test is performed with k maximum number of analyses, and are planned at each interim analysis j=1,…,k where a significance tests is performed. If the P value is below some pre-specified level _j, the trial is stopped. If the P-value is greater than _j the trial continues until the next planned interim analysis.The Pocock design has a group sequential design that has a fixed nominal level. The nominal significance level _j is a constant _* chosen to give an overall probablility _j of a Type I error. There are other opposing designs done by O’Brien and Fleming have that have different _j for each test. [11]•We want a big enough sample size to achieve a pre determined power for a particular alternative and a desired Type I error (usually 5%).•Type I error =P(declare a treatment difference |Ho).•The group sequential design declares a difference between groups if-|Z1|>B1 (stop at 1st interim),-|Z1<B1| but |Z2|>B2 (stop at second interim),-…-|Z1|<|B1|,|Z1|<B2,….,|Zk-1|<Bk-1, |ZK|>BK(last analysis)[6]-B1,B2,….Bk, the stopping boundaries,- K, the maximum number of looks, and- n, the number of patients responding since the previous look in each treatment group. [8]Choosing Boundaries*Pocock (1977) Biometrika 64,191-199: Pocock was the first to take this approach and divided type 1 error evenly across number of analyses. For instance, if K=3, each "k=.05/3=. 0167.It is provided clear guidelines for group sequential tests with given type 1 error and power, and has greater chance of stopping the trial early.O’Brien –Fleming (1979) Biometrics 35,549-556: This is an alternative to Pocock repeated significance tests. They ‘spend’ very little of the Type I error at beginning interim analyses, and gradually increasing it. It makes difficult to stop early, and thus p-values at end close to nominal (0.05) level.Fleming-Harrington-O’Brien (1984) Controlled Clinical Trials 5, 348-36It is similar to O’Brien –Fleming above, but less conservative.*{9], [3], and [8]Critical Values-Nominal P values:K=4 analyses, Type I error=0.05Pocock O’Brien-FlemingAnalysis cv P cv P1 2.36 0.016 4.08 .0000052 2.36 0.016 3.22 .00133 2.36 0.016 2.28 0.02284 2.36 0.016 2.040.0417(cv=critical value for Z statistic)[6]Problems with These Stopping Boundaries*•Pocock: At the end of the study, the nominal p-value is less than 0.05 but is not sufficiently small enough to achieve the significance based on the design. It requires the largest sample size to achieve specified power.•O’Brien-Fleming: Very Conservative, the boundaries may see too small during the first tests.•Fleming-Harrington-O’Brien: Middle ground between other two, but more similar to OF.*[3]Alternative approaches to Sequential and Group Sequential Designs*•Bayesian methodsThe Bayesian method mainly looks at the interpretation of the estimate of the difference instead of significance levels or confidence intervals [5]•Futility analysesFutility analysis occurs when a study ends early due to either:-when a considerable number of patients experience serious side effects-or you realize that evidence shows the results at the end of the trial are going to be negative.[10]Coclusion*•All interim analyses should be planned in advance and should be carefully laid out before doing the analysis. Avoid any unplanned interim analysis.•The schedule or considerations of analyses, and the stopping guidelines and their properties should also be carefully planned before the time of the first interimanalysis•When there is a Data Monitoring Committee (DMC), they should approve the procedure plan.•Any changes to the trial and then to the statistical procedures should be specified in the protocol at the earliest opportunity.•The main goal when selecting procedures should make sure overall probability of Type I error is controlled.•“You have to pay a price with an interim analysis, by living with a smaller alpha level at the end of your study”[10]*[1],[4],[8],References[1] Meinert, Curtis L. Clinical trials: design, conduct, and analysis.New York : Oxford University Press, 1986[2] Everitt, B.B. Statistical Methods for Medical Investigations. Oxford University Press[3]/~esg/TALKS/interimanalyses.ppt[4] www.bio.uu.nl/~biostat/seminar%20JC.ppt[5] Spiegel halter D.J., Freedman L.S., Par mar M.K.B. Bayesian approaches to randomized trials. J. R. Statistic. Soc. A. (1994) 157 357–416.[6] http://www.nurs.uoa.gr/EMR-IBS/Lecture2.pdf{7} .tw/documents/ activities/download/sw/(3)%20__.ppt{8}http://psg-/ticr/syllabus/courses/26/2005/01/20/Lecture/notes/Lecture3_20Jan05.pdf[9]/~mascj/psislides.pdf[10]/stats/plan/interim.asp[11]Eva Skovland, Repeated Significance Test on Accumulating Survival Data. The Norwegian Cancer Society and Section of Medical Statistics, University of Oslo, Oslo, Norway。

Repeated Measures ANOVA in SPSS

Repeated-Measures ANOVA in SPSSCorrect data formatting for a repeated-measures ANOVA in SPSS involves having a single line of data for each participant, with the repeated measures entered as separate variables on that same line (in this example, they are called “trial1,” “trial2,” “trial3,” and “trial4”). Note that this is different from the setup for a Hierarchical Linear Model, where you would have a separate line of data for each observation and repeat the subject number on each separate line, with a variable named “trial” that goes from 1 to 4 for each participant, and a separate variable called “score” that just has the number in it that corresponds to that trial for that participant.The procedure is found under “Analyze”/“General Linear Model”/“Repeated Measures.”Use the first pop-up dialog box to define your repeated-measures factor – this is how you tell SPSS that the four different “trial” variables are really all a single person’s scores over time on one variable. Give your variable a name (like “trial”), and specify how many different levels it has (i.e., how many times the observation was repeated). Be sureSelect the columns in your dataset that represent the various levels of the repeated-measures variable, and use the arrow button to move them into the “blanks” in the right-hand column.Next, specify your model. The within-subjects factors represent scores on the DV at each trial. Therefore, they will be treated as the dependent (criterion) variable for this analysis. For predictors, enter grouping variables (e.g., treatment vs. control) as “between-subjects factors,” and other interval/ratio-level predictors as “covariates.” In this example, participants’ anxiety level (“Anxiety”) and tension level (“Tension”) were both manipulated experimentally, so these are entered as grouping variables (“between-subjects factors”). Therefore, this is a 2 (two levels of anxiety) x 2 (two levels of tension) factorial repeated-measures ANOVA design.Use the “Options” button to open this window, and click on the check-box to select “Homogeneity Tests.” This will allow you to test the homogeneity of variance assumption for the repeated-measures dependent variable. This window also shows you all the different interactions that will be tested as part of your analysis. If you don’t want all of these results, you can select just specific main effects and interactions by using the“Model” button in the main dialog window. Click “Continue” to go on.One other type of output you might want is a graph showing the average change in scores on the dependent variable for individuals over time, maybe with the results sorted based on the experimental group the person is in. The “Plots” button on the main dialog box lets you do this. In this dialog box, the DV (repeated-measures variable) goes on the “horizontal axis” of the graph. If you just want to see that variable’s change over time, just enter that for the horizontal axis and leave the other fields blank. If you want to see separate lines on the graph for people in different groups, put the grouping variable into the “separate lines” box. Remember to hit the “Add” button to add your graph to the list that SPSS will provide.Now return to the main dialog box and hit “OK” to see the output.SPSS uses a multivariate analysis to detect repeated-measures effects. This approach assumes that there is some change from each time period to the next on the repeated measure. If you expect more of a “stepwise” pattern in your results, it may be advisable to test only the pre-post difference in the repeated measure. Alternately, you may want to consider using a different procedure like ANCOVA or HLM.The significant p-values show an effect of time (trial) on the dependent variable – a within-subjects effect reflected by the repeated measures. All four multivariate tests also show a significant interaction between trial and anxiety level, meaning that the level of anxiety induced in the participant had a significant effect on their performance over time. The effect of tension, by contrast, did not reach conventional levels of statistical significance. Because tension had a non-significant effect, it probably doesn’t make sense to look at the results for the three-way interaction between tension, anxiety, and time.In this case, the assumption of sphericity was not met (because the p-value of the test was significant, indicating a significant difference from the conditions under which the assumption holds true). Unfortunately, this means that we cannot rely on the multivariate tests examined above. The “epsilon” values on the right-hand side of this table are three different ways to calculate an appropriate adjustment to the degrees of freedom of the F-test. The next table shows revised results using each of these corrections. The Lower-Bound test is the most conservative; the Huynh-Feldt test is generally least conservative.The revised tests: This time, there is a significant effect of time (trial), but no interaction with either of the experimental variables.SPSS also automatically tests for nonlinear trends. This can be helpful if you think that an effect will be curvilinear with respect to time (for example, you might expect an effect strong at first, diminishing over time). This table shows the same significant linear effect of time on the DV as we saw in the previous analyses, plus a possible quadratic effect for the interaction between anxiety and time. This effect should be interpreted cautiously given the overall nonsignificant effect of anxiety and the fact that it only barely achieved the .05 cut-off for significance. Nevertheless, it may be worth further investigation.SPSS concludes the analysis with a univariate test, looking at the main effect of each predictor on the average of the four time intervals for the DV. I don’t recommend using this particular analysis, as it by definition ignores effects of time. If you really didn’t expect changes over time, you probably wouldn’t have used a repeated-measures ANOVA. But, this analysis may help you to see if there are any main effects of your IVs on your DV, if time did not have a significant effect in the analyses examined previously. If you found nonsignificant effects for time, this could at least help to suggest alternative analytic strategies for further research.Finally, we have the graphs that were specified in the “Plots” command. These clearly show the change over time (trial) in the DV. They also show the hint of a nonlinear effect of anxiety, as there are slight differences between the two anxiety groups on the type of change observed in the DV—you can see how the two groups seem to diverge at Trial 4. Again, this is not a firm conclusion (unless that was the effect we expected and that we were specifically testing for), but it might be worth further investigation.。

Hypothesis_Testing(统计学假设检验)

we might hypothesize that the mean IQ for UIC students is = 110. we might select a random sample of n = 100 UIC students.
2. Next, we obtain a random sample from the population. For example,
批注本地保存成功开通会员云端永久保存去开通
Statistics for Business (ENV)
Chapter 9
INTRODUCTION TO HYPOTHESIS TESTING
1
Hypothesis Testing
9.1
9.2 9.3
Null and Alternative Hypotheses and Errors in Testing z Tests about a Population with known s t Tests about a Population with unknown s
2
Hypothesis testing-1
Researchers usually collect data from a sample and then use the sample data to help answer questions about the population. Hypothesis testing is an inferential statistical process that uses limited information from the sample data as to reach a general conclusion about the population.

医学检测的英语作文范文

医学检测的英语作文范文标题，The Importance of Medical Testing。

Medical testing plays a crucial role in healthcare, aiding in the diagnosis, treatment, and prevention of various illnesses and diseases. In recent years, advancements in technology have greatly improved the accuracy and efficiency of medical tests, revolutionizing the field of healthcare. This essay explores thesignificance of medical testing, its different types, andits impact on individuals and society.Medical testing encompasses a wide range of diagnostic procedures conducted to assess the health status of individuals. These tests can detect diseases, monitor treatment effectiveness, and screen for potential health risks. One of the most common types of medical testing is laboratory testing, which includes blood tests, urine tests, and genetic testing. These tests analyze biological samples to identify abnormalities or markers indicative of certaindiseases or conditions.Blood tests, for example, measure various parameters such as cholesterol levels, blood sugar levels, and the presence of specific antibodies or pathogens. These tests are vital for diagnosing conditions like diabetes, cardiovascular disease, and infections. Similarly, urine tests can reveal important information about kidney function, urinary tract infections, and metabolic disorders.Genetic testing has emerged as a powerful tool in personalized medicine, allowing healthcare providers to assess an individual's genetic predisposition to certain diseases. By analyzing an individual's DNA, genetic tests can identify mutations or variations associated with conditions like cancer, cardiovascular disease, and hereditary disorders. This information enables healthcare professionals to tailor treatment plans and implement preventive measures based on an individual's geneticprofile.Imaging tests, such as X-rays, MRIs, and CT scans,provide detailed images of the body's internal structures, aiding in the diagnosis of injuries, tumors, and other abnormalities. These non-invasive tests allow healthcare providers to visualize the affected area and determine the appropriate course of action.In addition to diagnostic purposes, medical testing is instrumental in monitoring disease progression and treatment response. For individuals with chronic conditions such as diabetes, hypertension, or HIV, regular testing is essential for assessing disease management and adjusting treatment plans accordingly. By closely monitoring biomarkers and other indicators, healthcare providers can optimize treatment strategies and improve patient outcomes.Furthermore, medical testing plays a crucial role in disease prevention and public health initiatives. Screening tests, such as mammograms, Pap smears, and colonoscopies, aim to detect diseases in their early stages when treatment is most effective. These tests can identify precancerous lesions or early-stage tumors, enabling prompt intervention and potentially saving lives. Similarly, infectious diseasescreening, such as HIV testing and tuberculosis screening, is vital for preventing the spread of communicable diseases within communities.Despite its numerous benefits, medical testing is not without challenges and limitations. False positives and false negatives can occur, leading to unnecessary anxiety or missed diagnoses. Additionally, access to medicaltesting may be limited in certain regions or communities, exacerbating healthcare disparities. Efforts to address these challenges include improving testing accuracy through technological advancements, expanding access to testing services, and promoting public awareness of the importance of early detection and preventive care.In conclusion, medical testing plays a pivotal role in modern healthcare, facilitating early diagnosis, personalized treatment, and disease prevention. From laboratory tests to imaging studies to genetic analysis, medical testing encompasses a diverse array of diagnostic modalities that contribute to improved patient outcomes and population health. By leveraging the latest advancements intechnology and ensuring equitable access to testing services, we can continue to harness the power of medical testing to enhance healthcare delivery and promote overall well-being.This piece was inspired by various essays on the importance of medical testing found online. It reflects the significance of medical testing in healthcare and its various applications in diagnosis, treatment, and prevention.。

甲功七项的临床意义

PART TWO
甲功七项与内分泌系统调节 "甲功七项与内分泌系统调节是维持机体平衡的重要环节。
"
甲功七项的临床意义
甲状腺功能七项检查的临床意义
甲状腺激素在人体能量代谢、神经系统功能、消化系统功能、心血管系统功能等方面起着关键作用。甲亢（甲状腺功能亢进）时，T3、T4水平升高，导致机体基础代谢率增加，全身热量消耗增加，机体虚弱无力，常常出现心悸、多汗、手抖等表现。甲减（甲状腺功能减退）时，TSH水平升高， T3、T4水平降低，患者会出现畏寒、乏力、表情呆滞、反应迟钝等表现。
甲状腺功能检查：评估代谢率的关键
然而，当甲状腺激素水平异常时，例如甲亢或甲减，人体的代谢率就会受到影响。甲亢会导致甲状腺激素分泌过多，从而导致代谢率过高，可能出现心悸、多汗、易怒等症状。而甲减则会导致甲状腺激素分泌不足，从而导致代谢率降低，可能出现乏力、畏寒、食欲减退等症状。
因此，通过定期进行甲功七项检查，我们可以精确评估人体的甲状腺功能，及早发现和治疗甲状腺疾病，从而维护身体的正常代谢率，保持健康。此外，甲功七项检查还有助于我们评估其他与代谢相关的疾病，如糖尿病、肥胖症等。在这些疾病中，甲状腺功能异常往往是一个重要的影响因素。通过监测甲状腺功能，我们可以更好地理解这些疾病的发病机制，为治疗提供更准确的依据。综上所述，甲功七项检查在评估人体代谢率方面具有重要意义。它不仅可以精确反映人体的甲状腺功能，及早发现和治疗甲状腺疾病，还能帮助我们理解与代谢相关的其他疾病的发病机制，为治疗提供更准确的依
1.促甲状腺激素（TSH） TSH是反映甲状腺功能最为敏感的指标，也是临床上应用最广泛的指标。甲功七项中的TSH值主要由垂体分泌，主要用于反映甲状腺轴调节异常导致功能亢进。甲状腺功能减退或各种病因导致甲状腺激素合成障碍时，为维持正常生理功能，机体就会增加分泌TSH来刺激甲状腺使其加大分泌甲状腺激素以至保持机体正常代谢。另外，甲减的发生与否也会影响到血清TSH浓度，有临床数据显示当机体发生甲减超过一年时TSH明显增高，进而提高血清中浓度可能抑制机体分泌甲状腺激素引起反馈性的甲状腺激素分泌增多导致甲亢。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

医学检验英语作文

医学检验英语作文【中英文实用版】Medical Test English CompositionIn the realm of healthcare, medical tests play a pivotal role in diagnosing and monitoring various diseases.These tests, ranging from simple blood draws to complex imaging scans, are essential for ensuring the well-being of patients.This essay aims to shed light on the significance of medical tests in the English language.在医疗保健领域，医学检验对于诊断和监测各种疾病起着至关重要的作用。

这些检验项目从简单的抽血到复杂的影像扫描，都是确保患者健康的关键。

本文旨在用英语阐述医学检验的重要性。

The first and foremost advantage of medical tests is their ability to provide objective data for accurate diagnoses.For instance, blood tests can reveal the levels of various biomarkers, indicating the presence of diseases such as diabetes or heart conditions.In this way, medical tests serve as a cornerstone in the diagnostic process.医学检验的首要优势在于能够提供客观数据，以实现准确诊断。

关于实验室检测的英语作文

关于实验室检测的英语作文Laboratory testing is a cornerstone of scientific inquiry and plays a crucial role in advancing our understanding of the natural world. This essay will delve into the significance of lab testing, the various types of tests conducted, and the impact these tests have on research and development.Firstly, laboratory testing is essential for validating hypotheses and theories. Scientists often develop hypotheses based on observations and existing knowledge. Lab tests provide a controlled environment where these hypotheses can be rigorously tested, leading to the confirmation, modification, or rejection of the initial theory.Secondly, the types of laboratory tests are as diverse as the fields of study they support. For instance, in biology, tests such as PCR (Polymerase Chain Reaction) are used to amplify DNA sequences, allowing for genetic analysis. In chemistry, titrations and spectrophotometry are common methods for determining the concentration of substances and their interactions. In the medical field, diagnostic tests like blood panels and imaging studies are vital for disease detection and treatment monitoring.Thirdly, the accuracy and reliability of laboratory testing are paramount. To ensure the integrity of results, labs must adhere to strict protocols and quality control measures. This includes the use of calibrated equipment, standardizedprocedures, and the implementation of good laboratorypractices (GLP).Moreover, the impact of laboratory testing extends beyond the confines of the lab. It is instrumental in the development of new medicines, the monitoring of environmental conditions,and the enforcement of safety standards in various industries. For example, pharmaceutical companies rely on lab tests to evaluate the efficacy and safety of new drugs before they are approved for public use.In conclusion, laboratory testing is a fundamental aspect of the scientific process. It enables researchers to test their ideas, contributes to the body of scientific knowledge, and has practical applications that benefit society as a whole.As science continues to evolve, the role of laboratorytesting will remain indispensable, driving innovation and discovery in countless ways.。

STATISTICALLYSIGNIFICANT,BUTISITSIGNIFICANT

What Researchers Really Want/Need to Know
• Is the effect we see in our data real, or is it due to chance? • If we believe the effect is real, how large is the effect? • Given the size of the effect, is it of any practical use?
American Psychological Association Task Force
• The APA convened a task force in response to the 1994 American Psychologist article by Jacob Cohen, “The Earth is Round (p<.05)”
Yate’s View
In 1951 statistician, Frank Yates, made the following observation that use of the NHST--
“has caused scientific research workers to pay undue attention to the results of the tests of significance they perform on their data, and too little to the estimates of the magnitude of the effects they are investigating. . . . The emphasis on tests of significance, and the consideration of the results of each experiment in isolation, have had the unfortunate consequence that scientific workers have often regarded the execution of a test of significance on an experiment as the ultimate objective.”

shapiro-wilk test 的significance -回复

shapiro-wilk test 的significance -回复Shapiro-Wilk Test and Its Significance in Statistical AnalysisIntroduction: The Shapiro-Wilk test is a statistical test used to determine whether a given data set follows a normal distribution. It is a powerful tool for assessing the assumption of normality, which is often a requirement for many inferential statistical tests. In this article, we will discuss the step-by-step process of the Shapiro-Wilk test and its significance in statistical analysis.What is the Shapiro-Wilk Test?The Shapiro-Wilk test is a hypothesis test that aims to determine if a random sample comes from a normally distributed population. It was first proposed by Samuel Shapiro and Martin Wilk in 1965. The test is based on the correlation between the observed data and the corresponding normal scores, and it provides a statistical measure known as the W statistic.Step-by-Step Process of the Shapiro-Wilk Test:Step 1: State the null and alternative hypotheses. The null hypothesis (H0) assumes that the sample comes from a normally distributed population, while the alternative hypothesis (Ha) assumes otherwise.Step 2: Choose the significance level (α). This determines the threshold for rejecting the null hypothesis. Commonly used valuesfor αinclude 0.05 and 0.01.Step 3: Calculate the test statistic (W). This involves performing calculations based on the observed data and comparing it to the theoretical values from the normal distribution.Step 4: Obtain the critical value. This value is determined based on the significance level and the sample size. The critical value is used to make a decision on whether to reject the null hypothesis.Step 5: Compare the test statistic to the critical value. If the test statistic is less than the critical value, we fail to reject the null hypothesis, indicating that the data comes from a normally distributed population. Otherwise, if the test statistic is greater than the critical value, we reject the null hypothesis, suggesting that the data does not follow a normal distribution.Significance of the Shapiro-Wilk Test:1. Assessing the Assumption of Normality: Many statistical tests, such as t-tests and ANOVA, assume that the data comes from a normally distributed population. Violation of this assumption can lead to incorrect conclusions and biased estimates. By using the Shapiro-Wilk test, researchers can determine whether their data meets the assumption of normality, allowing for the appropriate use of these tests.2. Non-parametric Alternatives: In cases where the data doesnot follow a normal distribution, researchers can resort tonon-parametric tests that do not require the assumption of normality. However, these tests are often less powerful than their parametric counterparts. The Shapiro-Wilk test can help identify situations where non-parametric tests may be more appropriate.3. Data Transformation: If the data does not meet the assumption of normality, researchers may consider data transformation techniques to achieve normality. The Shapiro-Wilk test can be used to assess whether the transformation has successfully normalized the data.4. Robustness: The Shapiro-Wilk test is known for its robustness to both small and large departures from normality. It performs well with small sample sizes and is less affected by outliers compared to other normality tests, such as the Anderson-Darling test.Conclusion:The Shapiro-Wilk test is a widely used statistical test for assessing the assumption of normality in data. Its step-by-step process allows researchers to make informed decisions about the data analysis procedure and the selection of appropriate statistical tests. By determining whether the data follows a normal distribution or not, researchers can ensure the validity of theirresults and make appropriate interpretations. The significance of the Shapiro-Wilk test lies in its ability to guide statistical analysis and promote accurate inference in various research fields.。

应用于心理学中的多元显著性检验方法

应用于心理学中的多元显著性检验方法多元显著性检验方法（Multivariate Significance Tests）在心理学研究中得到了广泛地应用。

它是一种比较不同变量之间相互关系时使用的统计方法。

多元显著性检验方法对多个因素对多个变量的影响进行分析，探究各自对因变量的贡献。

在心理学中，研究人员关注的问题通常是多个因素间如何影响各个变量，例如人格特征与行为、学习方式与情绪状态等。

多元显著性检验方法正好可以满足这种研究需求。

它能够同时探究多个因素对多个变量的影响，并通过F值的显著性检验来确定哪些因素对哪些变量产生了显著的影响。

在具体的应用中，多元显著性检验方法可以应用于因子分析、聚类分析、线性回归分析、协方差分析、多元方差分析等多种场景。

例如，在人格特征研究中，研究人员可以使用多元显著性检验方法，将多个人格特征作为自变量，将行为表现作为因变量，通过统计分析得出各个人格特征对行为表现的影响程度；在学习研究中，研究人员可以使用多元显著性检验方法，将多个学习方式作为自变量，将学习成绩作为因变量，通过统计分析得出各种学习方式对学习成绩的贡献程度。

需要注意的是，多元显著性检验方法也存在一些限制。

首先，对于大规模的数据集而言，多元显著性检验方法可能会导致过拟合的问题，使得结果具有一定的不确定性；其次，在变量之间存在较强的相关性时，多元显著性检验方法也可能出现误差较大的情况。

因此，在使用多元显著性检验方法前，需要对数据的分布情况、变量之间的相关性等进行充分的探究。

总之，多元显著性检验方法是一种可以应用于心理学研究中的重要统计方法。

它能够帮助研究人员深入了解多个因素对多个变量的影响，从而更加准确地描述和预测人类行为、认知、情感等方面的表现。

logit模型随机参数的判断

logit模型随机参数的判断In the realm of statistical modeling, the logit model is a widely used tool for studying binary response data. Its popularity stems from its ability to model probabilities of binary outcomes as a function of predictor variables. When dealing with random parameters in the logit model, it is crucial to properly assess and interpret their effects.在统计建模领域中，logit模型是研究二元响应数据的一种广泛使用的工具。

其受欢迎程度源于其能够将二元结果的概率建模为预测变量的函数。

在处理logit模型中的随机参数时，正确评估和解释它们的影响至关重要。

One key aspect of analyzing random parameters in the logit model is the examination of their variability. This involves estimating the standard errors associated with the parameter estimates and conducting tests of significance to determine whether the parameters are statistically significant. The significance of a parameter indicates whether it has a meaningful impact on the predicted probabilities.分析logit模型中随机参数的一个关键方面是检查它们的变异性。

significant 数学

significant 数学
在数学中，“significant”这个词可能出现在几个上下文中。

下面是其中几个常见的例子：
1.统计显著性（Statistical Significance）：这是统计学中经常使用的一个概念。

当某个事件或实验
结果的观察频率或观测值与预期或模型的预测之间存在明显差异时，我们说这个结果是统计显著的。

通常，我们会使用p值或z分数等工具来评估这种显著性。

2.有效数字（Significant Figures）：在数值表示中，有效数字是指那些具体表示数值大小的数字。

例如，在数字12345中，“2”是一个有效数字，因为它确实代表了一个具体的数值。

与此相关的是“有效位数”，它是那些非零的数字。

3.重要样本（Significant Samples）：在进行统计推断或实验设计时，某些样本或数据点可能对结
果有显著影响。

这些样本被称为重要样本。

4.显著性检验（Significance Tests）：这是统计学中的一种方法，用于评估一个假设是否可以被数
据拒绝。

例如，t检验、z检验和卡方检验等都是显著性检验的例子。

在以上例子中，“significant”表示的是一种相对重要性或显著性，强调了某个数字、事件或结果相对于其他可能的值、事件或结果的特殊性或重要性。

在具体的上下文中，“significant”可以有不同的含义和解释，需要结合具体语境进行理解。