Individuals filing federal income tax returns prior to March 31 received an average refund

of $1056. Consider the population of "last-minute" filers who mail their tax return during

the last five days of the income tax period (typically April 10 to April 15).

a. A researcher suggests that a reason individuals wait until the last five days is that on

average these individuals receive lower refunds than do early filers. Develop appropriate

hypotheses such that rejection of H0 will support the researcher's contention.

b. For a sample of 400 individuals who filed a tax return between April 10 and 15, the

sample mean refund was $910. Based on prior experience a population standard deviation

of = $1600 may be assumed. What is the p-value?

c. At= .05, what is your conclusion?

d. Repeat the preceding hypothesis test using the critical value approach.