Question: A business study was conducted regarding gasoline purchases over a three-state area. The hypothesis was that the mean gas purchases differ from 15 gallons, which was the mean five years ago before the company acquired more customers in remote areas associated with increased oil drilling activity. (Chapter 10)

a. Write the null hypothesis:

b. If the number of mean sample measures was 60, at the 95% confidence level, what t-statistic is the critical value?

c. When you calculate the test statistic for your research, the test statistic is t= 3.7429. Do you reject or accept the NULL?

d. Why?