Income tax returns one year averaged $1,332 in refunds for taxpayers. One explanation of this figure is that taxpayers would rather
have the government keep back too much money during the year than owe it money at the end of the year. Suppose the average amount of tax at the end of a year is a refund of $1,332, with a standard deviation of $725. Assume that amounts owed or due on tax returns are normally distributed.
a. What proportion of the tax returns shows a refund greater than $2,000?
b. What proportion of the tax returns shows that the taxpayer owes money to the government?
c. What proportion of the tax returns shows a refund between $100 and $700?