... (sum of y)] [(n) (sum of (xx)) ]-[ (sum of x) (sum of x)] where: n = # of observations (36 months) x = rate of return for the S&P 500 Index y = rate of return for the fund 14 Dictionary of Financial ... average number of years that each dollar of unpaid principal due on the mortgage remains outstanding Average life is computed as the weighted 10 Dictionary of Financial and Business Terms Lico Reis ... Mac") and Federal National Mortgage Association (" Fannie Mae") Agency problem Conflicts of interest among stockholders, bondholders, and managers 5 Dictionary of Financial and Business Terms...