Two popular forms of mortgage are the thirty-year fixed-rate mortgage, where the borrower has thirty years to repay the loan at a constant rate, and the adjustable rate mortgage (arm), one version of which is for five years with the possibility of yearly changes in the interest rate. since the arm offers less certainty, its rates are usually lower than those of fixed-rate mortgages. test this hypothesis at the α = 0.01 level using the following sample of mortgage offerings for a loan of $250,000. do not assume the variances are equal.