(Solved): It is necessary for an automobile producer to estimate the number of miles per gallon achieved by i ...

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 140 cars is 28.6 miles and assume the standard deviation is 2.7 miles. Now suppose the car producer wants to test the hypothesis that $?$, the mean number of miles per gallon, is 29.2 against the alternative hypothesis that it is not 29.2 . Conduct a test using $?=.05$ by giving the following: (a) positive critical $z$ score (b) negative critical $z$ score (c) test statistic The final conclustion is A. There is not sufficient evidence to reject the null hypothesis that $?=29.2$. B. We can reject the null hypothesis that $?=29.2$ and accept that $??=29.2$.