DOC PREVIEW
TAMU STAT 303 - Exam 1

This preview shows page 1-2 out of 5 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

STAT303 Secs 508–510Spring 2004Exam #1Form AInstructor: Julie Hagen Carroll1. Don’t EVEN open this until you are told to do so.2. There are 20 multiple-choice questions on this exam, each worth 5 points. There is partial credit. Pleasemark your answers clearly on the scantron. Multiple marks will be counted wrong.3. You will have 60 minutes to finish this exam.4. If you are caught cheating or helping someone to cheat on this exam, you both will receive a grade ofzero on the exam. You must work alone.5. This exam is worth 100 points, and will constitute 20% of your final grade.6. Good luck!1STAT303 508–510 Exam #1, Form A Spring 20041. A researcher would like to know what percent ofthe parents of TAMU students support a certainissue. To answer her question, she selects a SRSof 30 students from the student body and bothparents from each student are incorporated intoher sample (so the sample size is 60). What isthe major flaw in this study?A. The researcher used a voluntary responsesample.B. The members of the sample are not inde-pendent.C. The researcher used a convenience sample.D. There are 2 populations, so there should be2 samples.E. There is no problem with this study.2. We have the following distribution:Male Female TotalsDemocrat 300 600 900Republican 500 300 800Other 200 100 300Totals 1000 1000 2000Consider the following questions:I. What is the proportion of males that areregistered as Democrats?II. What is the proportion of registeredDemocrats who are male?III. What is the proportion of all voters who aremale and registered Democrats?Choose the statement that best describes thequestions.A. Question I is about the marginal distri-bution of males, Question II describes ex-actly the same distribution and QuestionIII is the joint distribution of Demo cratsand Gender.B. Question I is about the marginal distribu-tion of Democrats, Question II describes ex-actly the same distribution and QuestionIII is the joint distribution of party affilia-tion and Gender.C. Question I is about the marginal distribu-tion of males, Question II describes theconditional distribution of Democrats andQuestion III is the joint distribution ofparty affiliation and Gender.D. Question I is about the marginal distribu-tion of males, Question II describes the con-ditional distribution of males and QuestionIII is the joint distribution of Gender.E. Question I is about the marginal distri-bution of males, Question II describes theconditional distribution of party affiliationsand Question III is the joint distribution ofparty affiliation and Gender.3. Suppose X ∼ N(4, 1.52). What is the approx-imate probability that an x chosen randomlyfrom this population will take a value between1 and 8.5?A. 0.9970B. 0.8150C. 0.9500D. 0.0265E. 0.97354. Which of the following is/are true about the cor-relation between two variables?A. Correlation always implies causation in anexperiment with numeric explanatory andresponse variables.B. Correlation between two categorical vari-ables can be described with the correlationcoefficient, r.C. A correlation coefficient of 0 implies there isno relationship between two numeric vari-ables.D. Two of the above are true.E. All of the abover are false.5. If the data in a normal q-plot is fairly linear andhas a mean of 10.76 and a standard deviation of3.93. What should be the approximate range ofthe data?A. 12B. 24C. 20D. 22E. 46. Suppose that you think there is an associationbetween a student’s gender and their choice ofmajor. If you collect data to test this claim,what graph/table would be the most appropriateto describe your data set?A. a two way tableB. side by side boxplotsC. a scatterplotD. a bar chartE. histograms for each explanatory variable2STAT303 508–510 Exam #1, Form A Spring 20047. Which of the following statements is/are true?A. Discrete random variables can only take oninteger values (whole numbers only).B. You can’t calculate a mean for a discreterandom variable since they can only takeon integer values.C. You can’t transform discrete random vari-able values into z-scores.D. All of the above are true.E. None of the above are true.Value Freq. Pct. Cum.Pct.0 17 1.6 1.62 7 0.7 2.23 31 2.9 5.14 22 2.1 7.25 22 2.1 9.36 61 5.7 15.07 27 2.5 17.58 165 15.4 32.99 39 3.6 36.610 49 4.6 41.211 38 3.6 44.712 300 28.1 72.813 28 2.6 75.414 77 7.2 82.615 12 1.1 83.716 103 9.6 93.417 12 1.1 94.518 24 2.2 96.719 13 1.2 97.920 22 2.1 100.0Totals 1069 100.08. What are the ’Five Number Summaries’ and ap-proximate shape of the distribution above?A. 0,25,50,75,100 and symmetricB. 0,32.9,72.8,75.4,100 and symmetricC. 0,5,10,15,20 and uniformD. 0,8,12,13,20 and normalE. 0,5,10,15,20 and normal9. Suppose a distribution is bell-shaped and has astandard deviation of 5. If 95% of the values ofthis distribution are greater than 12, what is themean of the distribution?A. 20.225B. 3.775C. 16.45D. 22E. 1710. Suppose X ∼ N(5, 62) and Z = (x − µ)/σ.Which of the following describes the distributionof Z?A. Z ∼ T (1)B. Z ∼ N(1, 02)C. Z ∼ N(0, 12)D. Z ∼ N(5, 62)E. Not enough information has been given toanswer this question.11. A researcher is interested in determining if caf-feine increases a student’s ability to solve logicproblems. She takes a SRS from TAMU mathmajors and a SRS of psychology majors. Bothgroups are asked to refrain from taking any caf-feine for 24 hours prior to the test. An hour be-fore the test, the math majors are given caffeineand the psychology majors are given a placebo.Is there a confounder in this study?A. Yes, caffeineB. Yes, genderC. Yes, majorD. Yes, the placeboE. No, there is no confounder.12. Referring to the scatterplot, what would happento the correlation if the outlier were removed?A. The correlation would decrease, and wouldgive a truer description of the strength ofthis linear relationship.B. The correlation would increase, and wouldgive a truer description of the strength ofthis linear relationship.C. The correlation would increase, but wouldgive no truer a description of the strengthof this linear relationship than before.D. The correlation would decrease, but wouldgive no truer a description of the strengthof this linear relationship than before.E. The correlation would not change signifi-cantly.3STAT303 508–510 Exam #1, Form A Spring 200413. In the histogram, the x-axis shows the midpointof each interval. Which of the following is/aretrue?A. The median falls in the 30’s and since it’sskewed to the right, the mean is larger


View Full Document

TAMU STAT 303 - Exam 1

Download Exam 1
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Exam 1 and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Exam 1 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?