STAT303 Secs 508–510Spring 2000Exam #1Form AInstructor: Julie Hagen CarrollPRINT Your Name:Thursday Section:Computer Number:1. Don’t EVEN open this until you are told to do so.2. Be sure to MARK your REGISTERED section number and your test form (A, B, C or D) on thescantron!3. Sign your name where indicated on your scantron and write your (Thursday) section number andcomputer number beside it. Also, PRINT your name at the top of this exam and include your (Thursday)section and computer number. You will get your scantron and exam back.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!1STAT303 508–510 Exam #1, Form A Spring 20001. Which of the following statements is/are true?A. The value of a parameter will change fromsample to sample.B. The IQR covers 50% of the range (spread)of the data.C. A z-score tells us how many standard devi-ations an observation is from its mean.D. All of the above are true statements.E. Exactly two of the above are true state-ments (excluding D.).x | 2 | 3 | 4 | 5 | 6 | 7 |------+---------------------------------------p(x) | 0.4 | 0.25 | 0.2 | 0.1 | 0.03 | 0.02 |2. The table above, from the Census Bureau, givesthe probability distribution for different familysizes in the U.S. What are the median,˜X, andmean,X, for this distribution?A.˜X = 4.5 and X = 5B.˜X = 4.5 and X = 4.5C.˜X = 3 and X = 3D.˜X = 3 and X = 3.17E.˜X = 4.5 and X = 3.173. Using the same distribution and assuming thatfamily sizes are independent of one another,what is the probability TWO families have 5members? (Remember the definition of indepen-dent!)A. 0.1 + 0.1 = 0.2B. 0.1 ∗ 0.1 = 0.01C. 0.1 + 0.1 − 0.01 = 0.19D. 0.1E. 0.1 + 0.1 + 0.01 = 0.214. Numbering the boxplots 1 through 6 from leftto right, which dataset mostly has a MEAN ofabout 50?A. You can’t tell the mean from a boxplot.B. 2C. 3D. 5E. 65. Which boxplot has the smallest InterquartileRange, IQR?A. 1B. 3C. 4D. 5E. 66. For which boxplot could we correctly apply theEmpirical Rule?A. The Empirical Rule could be applied to anyof the datasets.B. 1 and 5C. 1, 3 and 5D. 3 onlyE. The Empirical Rule could NOT be appliedto any of the datasets.7. Which boxplot matches the histogram above?A. 2B. 3C. 4D. 5E. 62STAT303 508–510 Exam #1, Form A Spring 20008. On the quiz, I gave everyone 75 points and thenadded 5 points for each of the five questionsanswered correctly, so the grade on the quiz,Y = 75 + 5 ∗ X, where X is the number of ques-tions answered correctly. If the average numberof questions answered correctly is X = 3 withstandard deviation sX= 1.5, what is the meanand standard deviation for the grade on the quiz?A.Y = 75 and sY= 5B. Y = 90 and sY= 1.5C. Y = 90 and sY= 7.5D. Y = 75 and sY= 1.5E. Y = 75 and sY= 7.59. Suppose I decided to add 5 points to everyone’squiz grade. Which of the following would betrue?A. The mean number of questions answeredcorrectly, X, would increase by 5.B. The mean grade on the quiz, Y , would in-crease by 5.C. The standard deviation for the grade on thequiz, sY, would increase by 5.D. Everyone’s z-score for the quiz would in-crease by 5.E. Exactly two of the above are true.10. Which of the following is not affected by outliers?A. the mean, xB. the median, ˜xC. neither the minimum or maximumD. the standard deviationE. Exactly two of the above are not affected11. If we know that a distribution is skewed to theleft, which of the following is true?A. No more than 25% of the observations willbe more than 2 standard deviations fromthe mean.B. About 5.5% (half of 11%) of the observa-tions will be more than 3 standard devia-tions below the mean.C. At least 94% of the observations will bewithin 4 standard deviations of the mean.D. All of the above are true.E. Exactly two of the above are true (exclud-ing D.).12. Which best describes the distribution BELOW?A. normalB. uniformC. skewed leftD. skewed rightE. symmetricPercentiles Smallest1% 0 05% 6 210% 9.5 625% 26 750% 34Largest75% 41 4990% 47.5 5295% 52 5799% 64 6413. How many outliers are there in the outputabove?A. at least 4B. 3C. 2D. 1E. none14. If you scored at the 90th percentile on the SAT,this would meanA. you scored 90% better than everyone elsewho took the exam.B. you scored better than 90 another peoplewho took the exam.C. you got 90% correct on the exam.D. 90% of the people who took the exam gotthe same amount correct as you did.E. you scored better than 90% of the peopletook the exam.15. Suppose George Jr.’s staff wants to figure outwhat proportion of the registered voters will votefor the younger Bush in the next primary. Theypoll 2150 citizens from the appropriate state andfind 82% are in favor of Bush. What is the pa-rameter of interest?A. µ, the true mean number of votes for Bushin the primaryB. π, the true mean percent of votes for Bushin the primaryC. 82%D. 2150E. p, the true proportion of votes for Bush inNovember, when it really counts3STAT303 508–510 Exam #1, Form A Spring 200016. Which of the following best describes the distri-bution above?A. The median is 2, and since it is skewed tothe right, the mean is greater than 2.B. The median is 2, and since it is skewed tothe right, the mean is less than 2.C. The median is 2, and since it is skewed tothe left, the mean is greater than 2.D. The median is 2, and since it is skewed tothe left, the mean is less than 2.E. The mean is 2, and since it is skewed to theright, the median is greater than 2.17. Which of the following are ’better’ statistics forthe distribution above?A. The mean and standard deviation are al-ways the best statistics to use.B. The mean and the IQR since there are out-liers.C. The median and the standard deviationsince there are outliers.D. The median and the IQR since there areoutliers.E. The median and the range since there areoutliers.| GenderCollege| F M | Total-----------+----------------------+----------AGLS | 4 15 | 19EDUC | 20 1 | 21ENGI | 5 14 | 19GEOS | 3 1 | 4LIBE | 14 13 | 27SCIE | 1 1 | 2VETM | 5 3 | 8-----------+----------------------+----------Total| 52 48 | 10018. If we chose a Male student from the distributionabove,
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