STAT303 Sec 508-510Fall 2007Exam #1Form AInstructor: Julie Hagen CarrollName:1. Don’t even open this until you are told to do so.2. All graphs are on the last page which you may remove.3. There are 20 multiple-choice questions on this exam, each worth 5 points. There is partial credit. Please mark youranswers clearly. Multiple marks will be counted wrong.4. You will have 60 minutes to finish this exam.5. If you have questions, please write out what you are thinking on the back of the page so that we can discuss it afterI return it to you.6. If you are caught cheating or helping someone to cheat on this exam, you both will receive a grade of zero on theexam. You must work alone.7. This exam is worth the same as a regular exam (this may differ from section to section.8. When you are finished please make sure you have marked your CORRECT section (Tuesday 12:45 is 508, 2:20 is 509,and 3:55 is 510) and FORM and 20 answers, then turn in JUST your scantron in the correct pile for your section.9. Good luck!1STAT303 sec 508-510 Exam #1, Form A Fall 20071. Which of the following is best describes the 5 Num-ber Summaries for the histogram labelled Floors of theStates’ Tallest Building? Note: all 50 states are repre-sented.A. The 5 Number Summaries are not displayed on ahistogram, so it cannot be determined from thisgraph.B. 5,25,45,55,105C. 0,25,50,75,100D. 0,25,45,75,110E. 0,45,80,100,1102. Referring to the previous histogram, what percent ofthe buildings have less than 20 floors?A. 6B. 6%C. 3%D. 12%E. Percents can’t be determined from this histor-gram.3. Based on a sample, the correlation coefficient r betweenaverage number of hours watching TV and GPR’s ofstudents at A&M is −0.7. The r for average number ofhours exercising and the same GPR’s is 0.25. Which ofthe following must be true?A. The relationship between watching TV and GPR’sis weaker than that of excerising and GPR’s sincethe correlation is smaller.B. There is practically no relationship between exer-cising and GPR’s.C. A high GPR is due to spending less time watchingTV.D. All of the above are true.E. None of the above are true.4. Which of the following is true in regards to samplingand sampling design?A. The principle of control is used to reduce the vari-ability of our sample statistics.B. The principle of randomization is used so that thedistribution of our sample statistics will be nor-mal.C. The principle of replication is used so that we getunbiased sample statistics.D. All of the above are true.E. None of the above are true.female male | TotalAsst Prof 125 227 | 352Assoc Prof 151 362 | 513Full Prof 81 647 | 728--------------------------+------Total 357 1236 | 15935. The table above breaks down Purdue’s 1593 facultymembers by gender and academic rank (data fromStatistics: Concepts and Controversies. The likelihood227/352 is best described as ‘given this sampleA. how likely a male is an assistant professor’.B. how likely an assistant professor is a male’.C. how likely you are male if you are an assistantprofessor’.D. how likely you are an assistant professor if you aremale’.E. how likely you are a male assistant professor’.6. Still referring to the Two-way table, which of the fol-lowing is/are true.A. There is obvious discrimination since the propro-tion of female full professors is so much smallerthan that of males.B. The proportion of females decreases as academicrank increases.C. Over half of the males are full professors.D. All of the above are true.E. Only two of the above are true.7. The likelihood of chosing a female associate professorfrom the table above isA. 151/1593B. 357/1593C. 151/513D. 513/1593E. 151/3572STAT303 sec 508-510 Exam #1, Form A Fall 20078. Suppose the mean score for the first exam is 70 witha standard deviation of 10. Assuming the data is bell-shaped, which of the following is true for an exam scoreof 90?A. The 90 means that this person did better than90% of the students who took the same exam.B. The 90 did better than almost 98% of the otherstudents since it has a z-score of 2.C. The 90 did better than almost 85% of the otherstudents since it has a z-score of 1.D. Since the z-score of the 90 is 2, this is the secondhighest score on the exam.E. All we can say is that the 90 made an A on thetest.9. If changes in a response variable are due to the effectsof the explanatory variable as well as from some othervariable, and we cannot distinguish between these ef-fects, we are said to haveA. a two-way correlation.B. a cause-and-effect relation between the explana-tory and response variables.C. a common response.D. a lurking variable.E. confounding.10. The scatterplot shows the relationship between the U.S.and South Korean judges for some Olympics event. Isthe American judge’s score a good predictor for theSouth Korean’s?A. Yes, since the slope is positive.B. Yes, since the correlation is strongly positive.C. Yes, but the correlation is only moderately posi-tive.D. No, the judging is secret, so the South Koreancouldn’t know how the American would vote.E. No, just because the correlation is strong, we can’tsay the American’s score could predict the SouthKorean’s.11. If the point (7.4, 9) were removed from the scatterplot,which of the following would be true?A. None of the bivariate statistics would changemuch.B. All of the bivariate statistics would change.C. The line would move, but the correlation coeffi-cient would stay basically the same.D. The correlation coefficient would increase, but theline would stay basically the same.E. None of the above are correct.12. Still referring to the scatterplot, which of the followingis/are true?A. Since the range of possible scores is 0 to 10, addinga point in the middle, (5, 5), would not change anyof the statistics.B. Any score below 7.0 for either judge would be po-tentially influential since none of the scores dis-played are that low.C. Since the judges use the same scale, the slope ofthe line must be 1.D. All of the above are true.E. Only two of the above are true.13. Suppose we have a set of 100 (x, y) points. If we mulit-ply all of the x’s by 10, thenA. the mean and standard deviation of the x’s will be10 times bigger.B. the slope and intercept of the regression line willbe 1/10 of their original values (10 times smaller).C. the z-scores for both x and y will stay the same.D. All of the above are true.E. Only two of the above are true.14. Which of the following is/are true about the histogramlabelled Year?A. It
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