A study is performed in a large southern town to determine whether the average weekly grocery bill per four-person family in the town is significantly different from the national average. A random sample of the weekly grocery bills of four-person families in this town is given in the file P09_06.xlsx.
a. Identify the null and alternative hypotheses for this situation.
b. Assume that the national average weekly grocery bill for a four-person family is $100. Is the sample evidence statistically significant? If so, at what significance levels can you reject the null hypothesis?
c. For which values of the sample mean (i.e., average weekly grocery bill) would you reject the null hypothesis at the 1% significance level? For which values of the sample mean would you reject the null hypothesis at the 10% level?