Question: 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 appro-

priate 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 1 0 and 1 5, the

sample mean refund was $91 0. Based on prior experience a population standard devi-

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

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

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