STAT303 Secs 102 & 103Summer I 2001Exam #1Form AInstructor: Julie Hagen Carroll1. Don’t EVEN open this until you are told to do so.2. Be sure to mark your section number and your test form (A, B, C or D) on the scantron!3. Sign your name where indicated on your scantron and write your section number and computer numberbeside it. You will NOT get your scantron and exam back, but I will keep them in case there is aproblem.4. 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.5. You will have 60 minutes to finish this exam.6. 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.7. This exam is worth 100 points, and will constitute 20% of your final grade.8. Good luck! Remember 1 down, only 3 to go!1STAT303 102 & 103 Exam #1, Form A Summer I 20011. The boxplot above shows ages for (F)females and(M)males in a study. Which of the followingstatements is true based on the graph?A. Males are younger than females.B. Although each of the 5 numbers representedin a boxplot is less for males than females,some males are older than some females inthe study.C. The distribution for both females and malesis slightly skewed to the right.D. Two of the above are true.E. None of the above are true.2. Which of the following best describes a randomsample?A. all samples from the population have thesame chance of being selected.B. all values in the population have the samechance of being selected.C. all values in the population are representedin the sample.D. all means of the population are representedin the sample.E. all values must be equally represented in thesample.| GenderTablets| F M | Total-------+----------------------+----------1 | 2 3 | 52 | 4 6 | 103 | 2 2 | 44 | 0 1 | 1-------+----------------------+----------Total| 8 12 | 20Pearson chi2(3) = 0.8333 Pr = 0.8413. Again, we’re looking at a study done on malesand females. The table above shows how manytablets were taken. Who is more likely to take 2tablets?A. Males since 6 vs. only 4 females took 2tablets.B. Males since 60% of the people who took 2tablets are male.C. It’s equal since half of each males and fe-males took 2 tablets.D. Males since 30%(6/20) vs. 20%(4/20) fe-males took 2 tablets.E. It can’t be determined from the informationgiven.4. Still using the previous table, what is the prob-ability that a person took only 1 tablet?A. 2/5B. 3/5C. 2/20D. 3/20E. 5/205. A nine-year-old genius appeared on The DavidLetterman Show. Dave asked him what his IQwas, and he replied that it was “off the bellcurve”. For his IQ to be an outlier about howlarge must it be? NOTE: Assume IQ’s are nor-mally distributed with mean = 100 and standarddeviation = 15.A. over 130B. over 115C. over 100D. over 150E. more information is needed2STAT303 102 & 103 Exam #1, Form A Summer I 20016. Which of the following best describes the graphabove?A. The data is skewed to the right, so themean, ¯x, which is about 20, is greater thanthe median, ˜x.B. The data is skewed to the left, so the mean,¯x, which is about 20, is greater than themedian, ˜x.C. The data is skewed to the right, so the me-dian, ˜x, which is about 20, is greater thanthe mean, ¯x.D. The data is skewed to the left, so the me-dian, ˜x, which is about 20, is greater thanthe mean, ¯x.E. The data is skewed to the right, so themean, ¯x, which is about 20, is less than themedian, ˜x.7. If the smallest value, 19.97, was misrecorded, andwe corrected it and changed it to 19.99, whatwould happen?A. Nothing since it’s basically still the samedata.B. The mean and median would increase.C. The mean would increase, but the medianwould decrease.D. The mean would increase, but the standarddeviation decrease.E. The mean and standard deviation would in-crease.8. If your score on this exam equals the 80th per-centile, thenA. you got 80% correct on the test.B. you did better than 20% all of the STAT30Xstudents.C. you did better than 80% all of the STAT30Xstudents.D. you did better than 20% of the STAT30Xstudents who took this exam.E. you did better than 80% of the STAT30Xstudents who took this exam.9. Which of the following is true?A. Sample surveys provided no useful informa-tion since they are not random.B. No inferences can be made from sample sur-veys since they are not random.C. Randomized experiments can never be donein medical settings since it’s unethical to‘make someone sick’.D. Randomized experiments are always thepreferred sampling method.E. All of the above statements are false.25 53 70 75 90 90 91 95 95 95 95 96100 105 110 115 12010. What is the median, ˜x, for the data above andwhy?A. 95 because it is the middle number.B. 95 because it is the most common number.C. 95 because 120 − 25 = 95.D. 47.5 because (120 − 25)/2 = 47.5E. 84 because it is the average.11. Which of the following is true about z-scores?A. You can use them to compare unlike sam-ples (ones with different means and sd’s).B. They are not affected by shift or scaleschanges.C. They always have a mean of 0 and standarddeviation of 1.D. All of the above are true.E. Exactly two of the above are true.3STAT303 102 & 103 Exam #1, Form A Summer I 2001Age| Freq. Percent Cum.------+---------------------------------32 | 1 5.00 5.0037 | 1 5.00 10.0039 | 1 5.00 15.0040 | 1 5.00 20.0041 | 3 15.00 35.0042 | 2 10.00 45.0043 | 1 5.00 50.0044 | 1 5.00 55.0045 | 3 15.00 70.0046 | 1 5.00 75.0047 | 2 10.00 85.0049 | 1 5.00 90.0050 | 1 5.00 95.0051 | 1 5.00 100.00------+---------------------------------Total | 20 100.0012. What are the 5 Number Summary numbers forthe output above and what is the shape of thedistribution?A. 32,40,43,46,51B. 32,40,43.5,47,51C. 32,36.5,41.5,46.5,51D. 32,41,43.5,46.5,51E. 32,41,44,47,5113. Still using the previous table, which of the fol-lowing best describes the point, 32?A. It is the minimum value.B. It is the outlier since it is more than1.5∗IQR’s from the first quartile, Q1.C. It is an outlier since there is a gap between32 and the next point, 37.D. It is an outlier since it is the furthest fromthe median.E. It is an outlier since it is the furthest fromthe mean.14. Which of the following statistics will changewhen you add 10 to each observation in adataset?A. the sample meanB. the sample medianC. the sample standard deviationD. both A. and B.E. both A. and C.15. Is the Empirical Rule
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