Information collected at a local university indicates that students are working, on average (a value for m) 15.23 hours per week while in school. Information collected from a random sample of 25 fraternity members, however, reveals a mean of 12.34 hours per week with a standard deviation (s) of 2.50 hours. Assume that you're working at the .05 level of significance.
a. State an appropriate null hypothesis.
b. What is the value of the calculated test statistic (t)?
c. Identify the critical value.
d. State your conclusion.