MATH 227 STATISTICS FINAL EXAM - West Los Angeles College

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2.) Modern medical practice tells us not to encourage babies to become too fat. 14 females took part in a lifelong experiment , where bivariate data was collected on each of the subjects. Let the predictor (explanatory) variable x represent the weight (in lbs) of the subject as a 1-year old baby. Let the response variable y represent the weight (in lbs) of the subject as a 30-year old adult. The summary statistics are as follows: ∑ x = 300 ∑ y = 1775 xy = 38,220 ∑ a.) Calculate SS xx , SS yy , and SS xy . 2 ∑ x = 6572 2 ∑ y = 226,125 b.) Calculate r . Interpret this value in the context of the problem. c.) Assume the equation of the sample regression line is y = 99.25 + 1.285x. What is the value of ˆβ 1, and interpret this value in the context of the problem. d.) Use x = 20 in regression line to find the corresponding value for y . e.) Give two interpretations of this corresponding y value, in terms of the above problem. Be as specific as possible. 18
3.) Sample bivariate data indicates a correlation between the number of cigarettes a person smokes, and the incidence of pancreatic cancer. The correlation coefficient, r, is 0.93. Circle TRUE or FALSE to the following statements, and EXPLAIN YOUR ANSWERS. a) There is a strong linear relationship between the number of cigarettes a person smokes and the incidence of pancreatic cancer. TRUE or FALSE Explanation ____________________________________________________________________ b) The information indicates that smoking causes pancreatic cancer. TRUE or FALSE Explanation ____________________________________________________________________ c) This regression equation relating smoking and pancreatic cancer is more useful than a regression equation using data for which r = -0.98. TRUE or FALSE Explanation ____________________________________________________________________ d) The slope of the regression equation is negative. TRUE or FALSE Explanation _____________________________________________________________________ e) About 86% of the variation in the incidence of pancreatic cancer is due to the variation in the number of cigarettes a person smokes. TRUE or FALSE Explanation _____________________________________________________________________ f) If you were testing H0 : β 1 = 0 vs. Ha : β1 ≠ 0, you would probably reject H 0 . TRUE or FALSE Explanation _____________________________________________________________________ 19
Page 1 and 2: MATH 227 STATISTICS FINAL EXAM M227
Page 3 and 4: 12. The large sample z test for µ
Page 5 and 6: 37. A discrete numerical variable i
Page 7 and 8: 51. Chebychev's Rule states that th
Page 9 and 10: 60. In the construction of confiden
Page 11 and 12: For problems 70 through 80, conside
Page 13 and 14: 81. In the formula for 2 s , the de
Page 15 and 16: For problems 91 through 94, conside
Page 17: PART III: SHOW ALL WORK FOR FULL CR
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MATH 227 STATISTICS FINAL EXAM - West Los Angeles College

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