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).The null hypothesis is that the average refund of last-minute filers is equal to or greater than $1056. The alternative hypothesis is that their average refund is smaller than $1056. 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 deviationmay be assumed $1600. What is the p-value?