Question

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 110 cars is 27.5 miles and assume the standard deviation is 3.3 miles. Now suppose the car producer wants to test the hypothesis that μ, the mean number of miles per gallon, is 24.7 against the alternative hypothesis that it is not 24.7. Conduct a test using α=.05 by giving the following:

(a)    positive critical z score    

(b)    negative critical z score

(c)    test statistic  

Answer 1

(a)    positive critical z score    = 1.96

(b)    negative critical z score   = - 1.96

(c)    test statistic = 8.9