3. Federal Tax Returns. According to the federal income tax returns prior minute" filers who mail their tax return du ays of the income tax period (typically April 10 to April 15) a) A researcher suggests that a reason individual wait until the last five days is that on average these individuals receive lower refunds than do early filers. Develop appropriate hypothesis such that rejection of HO 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 o-$1600 may be assumed. What is the p-value