Question

016 7. The following data give the speeds (mi/hr), as measured by radar of 16 cars traveling on the interstate 1-15. Assume the population is normal population. 75 72 80 68 76 74 71 78 82 62 65 70 64 79 74 66 a) What is point estimate of the mean and standard deviation of all cars traveling on this highway. b) Compute the 95% confidence interval for the mean speed of all cars traveling on this highway. c) Compute the 95% confidence interval for the standard deviation of all cars traveling on this highway.

Answer 1

16 no. of observations, n=16. sample mean to I EX= 75+12+ 80 +68+ ... 166 - +2,25 Sample valiance se i ECR-ng st = t (45-42.25 g ² + ... + (66-42.25 32 ] = 36.7333 Se r 3607333 & 6006 a point estunate of mean is û za e (72.25) point estimate of standard duration sa [6006) 6 95% confidence internal for the mean is (atte & z (+2.25 + 2:131x6:06) = (69.02, 45148) e [69.02 L 44 45 48 ) & 95th confidence internal for standard duration & is r (m-tls? (14) s2 1 = (16-1)(36.7333), (16-1) (36.4333) 7 550.9995 550.9995 , 530.9995 7 V 27.4888 v 6.262 = (4.48 9.38) re 14.48 LTL 9.38)