Statistics Quiz 9 version 1 name: 1. The paired data below consist of the costs of advertising (in thousands of dollars) and the number of products sold (in thousands): Find the value of the linear correlation coefficient r . 2. The paired data below consist of the length of random bears in inches and their weight in pounds. Find and use the correlation equation to predict the weight of a bear that measures 41 cost number 3.0 16.0 10.0 47.0 A r = 0.9918 D r = 0.7168 8.0 40.0 10.0 60.0 11.0 60.0 r = 1.0918 B o o C r = 0.9643 inches. inches lbs A 61.0 600.0 52.0 568.0 49.0 450.0 y = 416.705 lbs 67.0 656.0 64.0 576.0 61.0 688.0 y = 448.705 lbs B 57.0 534.0 o o y = 420.705 lbs C D None of these 3. Ten pairs of data yield r = 0.978 and the regression equation y = 9x + 8. Also, y = 1 What is the best predicted value of y A 53 these 4. Given: There is a significant linear correlation between the number of homicides in a town and the number of movie theaters in a town. Conclusion (True or False): Building more o o for x = 5 ? 3 B C 5 D 1 E None of o o movie theaters will cause the homicide rate to rise. A 5. In testing for correlation between two variables, the best fitting line is often call the regression equation and denoted as o o False B True B y = b1 x + b0 C y = b1 x + b0 A D y = 1 x + 0 y = 1 x + 0 E 6. In testing for correlation the relationship between two variables, the best fitting line is often call the regression equation and denoted as None of these B b1 = C xy ( x) ( y) 2 n ( x2 ) ( x) ( 2 ) ( y) x ( x) ( xy) b0 = 2 n ( x2 ) ( x) y = b1 x + b0 What formula is used to compute the slope of this line and its o y intercept? o n D b1 = n xy ( x) ( y) 2 n ( x ) ( x) A b1 = n xy + ( x) ( y) 2 n ( x2 ) ( x) 7. The paired data below consist of the test scores of some randomly selected students and the number of hours they studied for the test. Find the value of the linear correlation coefficient 2017 daabz.com E ( 2 ) ( y) x + ( x) ( xy) b0 = 2 n ( x2 ) ( x) r. hours score Statistics Quiz 9 version 1 2.0 12.0 6.0 44.0 6.0 37.0 6.0 38.0 7.0 46.0 7.0 45.0 14.0 94.0 page 1 of 3 Statistics Quiz 9 version 1 (page 2/ 3) o o 8. Ten pairs of data yield r = 0.944 and the regression equation y = 3x + 6. Also, y = 3.1 What is the best predicted value of A r = 0.9078 D None of these B r = 1.0558 C r = 0.9958 o o y for x = 6 ? A 2 these B 3 C 3.1 D 24 E None of 9. The paired data below consist of the length of random bears in inches and their weight in pounds. Find the value of the linear correlation coefficient r. in lbs 55.0 608.0 39.0 454.0 A r = 0.8937 B r = 0.8087 C r = 1.1112 D None of these 32.0 300.0 43.0 402.0 55.0 504.0 o o 10. The paired data below consist of the length of random bears in inches and their weight in pounds. Find and use the correlation equation to predict the weight of a bear that measures 62 inches. 11. Find the critical values of t given the number of pairs of data n = 12 and the o significance level = 0.05 as used to test for correlation. o inches lbs 62.0 584.0 66.0 624.0 y = 629.765 lbs A 44.0 514.0 B 67.0 700.0 55.0 596.0 y = 651.765 lbs 36.0 284.0 C 47.0 550.0 o o y = 625.765 lbs D None of these A t = 0.6003 D None of these B t = 2.2281 C t = 3.576 12. The paired data below consist of the length of random bears in inches and their weight in pounds. Find the value of the linear correlation coefficient r . in lbs 52.0 482.0 68.0 732.0 A r = 0.9192 B r = 0.9367 C r = 1.0967 D None of these 61.0 626.0 59.0 566.0 38.0 424.0 64.0 614.0 o o 13. In testing for correlation the relationship between two variables, the best fitting line is often call the regression equation and denoted as B b1 = y = b1 x + b0 n C What formula is used to compute the slope of this line and its y intercept? o o b1 = n D A b0 = ( ( ) y) ( x) ( xy) 2 2 n ( x ) ( x) x2 b1 = E 14. Find the value of the linear correlation coefficient r . x y 8.0 7.0 5.0 10.0 7.0 5.0 7.0 6.0 10.0 6.0 n xy ( x) ( y) 2 n ( x ) ( x) xy + ( x) ( y) 2 2 n ( x ) ( x) xy ( x) ( y) 2 2 n ( x ) ( x) None of these A r = 0.6153 D r = 0.3153 B r = 0.0353 C r = 0.7353 o o 15. 2017 daabz.com Statistics Quiz 9 version 1 page 2 of 3 Statistics Quiz 9 version 1 (page 3/ 3) Ten pairs of data yield r = 0.168 and the regression equation y = 9x + 6. Also, 69 A 16. Given: There is a significant linear correlation between the number of homicides in a town and the number of movie theaters in a town. Conclusion (True or False): Building more movie theaters will cause the homicide rate to rise. 17. The paired data below consist of the length of random bears in inches and their weight in pounds. Find the correlation equation. 9.9 B 5 C A True inches lbs B 39.0 372.0 64.0 672.0 30.0 242.0 51.0 442.0 D 44.0 366.0 39.0 360.0 2017 daabz.com 46.0 446.0 56.0 630.0 t= t= t2 n 2 + t2 44.0 398.0 o o y = 11.316x + C r 1+r 2 n2 D E 20. The paired data below consist of the length of random bears in inches and their weight in pounds. Find the correlation equation. 68.0 628.0 47.0 454.0 C t2 n 1 + t2 19. For n = 14 pairs of data, at significance level = 0.01, we would support the claim that the two variables are correlated if our test correlation coefficient r o was beyond which critical r values? o 67.0 658.0 65.0 618.0 y = 11.316x + 11.841 B B 57.0 512.0 None of these None of these A inches lbs E False y = 11.841x + 95.775 A 18. In testing for correlation the relationship between the t in the t-distribution o and r , the Pearson correlation coefficient is given by: o r2 = 4 D o o 95.35 r= o o y = 9.9 What is the best predicted value of y for x = 7 ? 44.0 412.0 68.0 684.0 33.0 272.0 r 1r 2 n2 None of these A r = 0.6614 D None of these B r = 0.6928 C r = 0.6999 o o A y = 10.864x + 11.939 11.939x + 67.499 Statistics Quiz 9 version 1 D B y = 10.864x + 67.499 C y = y = 11.939x 67.599 page 3 of 3