STAT303 Secs 508–510Fall 2000Exam #1Form AInstructor: Julie Hagen CarrollOctober 25, 20001. 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. You may keep your exam.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 Fall 20001. Which of the following statements is/are true?A. The value of the median will change if youadd 10 to the maximum in a dataset.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.).2. Which of the following is NOT affected by out-liers?A. the mean, ¯xB. the z-scoresC. the correlation coefficientD. Exactly two of the above are not affected.E. All of the ARE affected by outliers.3. Suppose you know that a distribution is bell-shaped, with mean,x = 30 and standard de-viation, sx= 4. Approximately what percent ofthe data will fall between 22 and 34?A. about 95%B. between 50 and 68%C. about 80%D. between 95 and 100%E. about 75%4. Numbering the boxplots 1 through 4 from left toright, which distribution is approximately uni-form?A. You can’t tell by looking at a boxplot.B. 3 only since it’s the most spread out.C. 4 only since it’s the most symmetric.D. Both 3 and 4 are uniform.E. None of the boxplots are uniform.5. Which boxplot has an Interquartile Range, IQR,of about 20?A. 1B. 2C. 3D. 4E. 1,2 and 4 are all the same.6. When can we correctly apply the EmpiricalRule?A. The Empirical Rule can be applied to anyof the datasets.B. Only if the data is bell-shaped.C. Only if the data is symmetric.D. All of the above are true.E. Exactly two of the above are true.7. Which of the following are ’better’ statistics forthe distribution above?A. The median and the range since the data isskewed.B. The median and the IQR since the data isskewed.C. The mean and the standard deviation sincethe data is skewed.D. The mean and the IQR since the data isskewed.E. The median and standard deviation are al-ways the best statistics to use.2STAT303 508–510 Exam #1, Form A Fall 20008. Suppose you know that a distribution is bell-shaaped with mean, ¯x = 25 and standard de-viation, sx= 2, what would be the approximate98th percentile?A. 0.98B. 98% of 25 = 24.5C. about 27D. about 29E. about 319. If we know that a distribution is skewed to theright, which of the following is true?A. The mean is smaller than the median.B. Outliers would most likely be to the left.C. The histogram would be shorter on the left.D. All of the above are true.E. None of the above are true.Percentiles Smallest1% 22 225% 26 2210% 32.5 2625% 37 2850% 52Largest75% 65 7590% 73 7795% 77 7899% 79 7910. How many outliers are there in the outputabove?A. at least 4B. 3C. 2D. 1E. none11. Which best describes the distribution in theproblem above?A. normalB. uniformC. skewed leftD. skewed rightE. symmetric12. Which of the following is the best approximationof the linear equation for this data?A. y = 90 + 2 ∗ xB. y = 50 + 2 ∗ xC. y = 90 + 0.5 ∗ xD. y = 50 + 0.5 ∗ xE. y = 150 + 50 ∗ x13. If the point (100,60) was added to the previ-ous scatterplot, which of the following would betrue?A. It would be an outlier, so the correlationwould decrease, but the slope would beabout the same.B. It would be an outlier, so the correlationwould increase, but the slope would beabout the same.C. It would be an influential point, so the slopeand intercept would change.D. It would be an outlier, so the correlationand the slope would increase.E. It would be an influential point, so the cor-relation would change, but the slope wouldbe about the same.14. If we know the data is bell-shaped, which of thefollowing would be true?A. The z-score for the median is 0.B. The z-score for the minimum is between −3and −4.C. The length of the IQR is less than 2.D. All of the above are true.E. Exactly two of the above are true.3STAT303 508–510 Exam #1, Form A Fall 200015. Which of the following best describes the distri-bution above?A. The mean is approximately 50 and the stan-dard deviation is about 10.B. The mean is approximately 50 and the stan-dard deviation is about 20.C. The median is approximately 50 and theinterquartile range is about 10.D. Exactly two of the above are true.E. You cannot tell the mean and standard de-viation from a histogram.| GenderDriver| F M | Total------+-----------------+-------aggres| 37 31 | 68passve| 14 16 | 30timid| 1 1 | 2------+-----------------+-------Total| 52 48 | 100Pearson chi2(2) = 0.5036 Pr = 0.777(p-value)16. Are ‘type of Driver’(aggressive, passive or timid)and ‘Gender’ statistically related?A. Yes, they are statistically related becausethe p-value is large.B. No, they are not statistically related be-cause the p-value is large.C. Yes, males are more aggressive than fe-males.D. No, only 1 male and 1 female are timiddrivers.E. We would need the correlation coefficient totell the strength of the relationship.17. Using the previous table, how likely are you tobe an aggressive driver if you are female?A. 37/52B. 37/68C. 68/100D. 52/68E. 37/10018. How likely are you to be a passive male driver?A. 16/48B. 16/30C. 30/100D. 16/100E. 48/10019. Which of the following is NOT true?A. Social Security Number is a discrete nu-meric variable.B. Classification is a an ordinal variable.C. Height is a continuous numeric variable.D. Number of cars that just ran the red lightis a discrete numeric variable.E. All of the above are true.20. How would you describe the correlation of thedata above?A. Strongly negativeB. Moderately negativeC. WeakD. Moderately positiveE. Strongly
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