STAT2004Exam1-Solns

STAT2004Exam1-Solns - when there are 25 cops in the park....

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You have 50 minutes to complete this exam. For each question, choose the most correct response. You are allowed a calculator and both sides of a standard 8.5”x11” crib sheet. This exam is closed- book and closed-notes. A student is interested in studying the ages his professors finally earned tenure. He sampled six professors and got the following information: age: 3 5 4 1 5 0 3 9 4 2 40 1. What is the average age for making tenure? a) 247 b) 41.167 c) 49.4 d) 40.5
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2. What age is the 30 th percentile? a) 41 b) 35 c) 37 d) 39 3. What age is the mode? a) 40.5 b) 41.167 c) 42 d) there is no mode 4. = 10291 ) ( 2 i x What is the standard deviation? a) 4.956 b) 24.567 c) 20.472 d) 4.525
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A study was done to see whether the number of police in a park on a given day affected the number of muggings. The following data were obtained: police: 2 5 ? 8 1 0 13 muggings: 1 2 1 1 9 5 ? 2 77 0 . 90 5 . 73 7 5 . 7 - = = = = = XY YY XX SS SS SS y x 5. What is 2 x s ? a) 411 b) 68.5 c) 3.834 d) 14.7 6. What is b ? a) -1.048 b) 14.857 c) -.856 d) 1.224
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7. What is r ? a) -.0116 b) .8963 c) -.9467 d) .0116 8. True or False? It would be extrapolation to use this equation to predict the number of muggings
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Unformatted text preview: when there are 25 cops in the park. a) True b) False 9. Which of the following is true about standardized values? a) s = 1 b) 1 = z c) s = 0 d) 1 < < z 10. Which of the following is not a resistant statistic? a) mean b) median c) mode d) IQR 11. True or False? The sample median will always be a number that was observed in the data set. a) True b) False 12. True or False? The following distribution is skewed right. 33 mode 32 ~ 28 = = = x x a) True b) False 13. What is the IQR? 41 24 20 15 10 4 3 2 1 = = = = = Q Q Q Q Q a) 21 b) 9 c) 4 d) 26 14. True or False? If r is positive, then a in our regression equation must also be positive. a) True b) False 15. True or False? b from the regression equation will always be between -1 and +1 ) 1 1 ( -b . a) True b) False 16. What is the standardized value for 10? 582 . 2 , 667 . 6 , 11 ~ , 667 . 11 2 = = = = s s x x a) .646 b)-.646 c)-.387 d) .250...
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This note was uploaded on 03/31/2008 for the course STAT 2004 taught by Professor Melutz during the Fall '07 term at Virginia Tech.

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STAT2004Exam1-Solns - when there are 25 cops in the park....

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