Question

(1 point) It is necessary for an automobile producer to estimate the number of miles per gallon achieved by its cars. Suppose that the sample mean for a random sample of 100 cars is 30.6 miles and assume the standard deviation is 3 miles. Now suppose the car producer wants to test the hypothesis that u, the mean number of miles per gallon, is 30.4 against the alternative hypothesis that it is not 30.4. Conduct a test using a = .05 by giving the following: (a) positive critical z score (b) negative critical z score (c) test statistic Note: Round off your answers to two decimal places. The final conclustion is A. We can reject the null hypothesis that u = 30.4 and accept that u = 30.4. B. There is not sufficient evidence to reject the null hypothesis that u = 30.4.

Answer 1

Date: Given : na100 = 30.6 ; = 3 To test Ho! U = 30.4 Hii U + 30.4 At X = 0.05 critical value is 2- critical 2 20.015:-1.96 +1.96 2 col positive critical 2- Score 1.96 (b) negative critical 2-score -1.96 cc) Test statistic Z X- olm 30.6 - 30.4 31 Too za 2 - 0.2 0.3 2 . 0.67 Since 2 < 1.96 fail to refect Но There is not sufficient evidence to reject the null hypothesis that M = 30.4