Based on current dividend yields and expected capital gains, the expected rates of return on portfolios a and b are 11% and 14%, respectively. the beta of a is .8, while that of b is 1.5. the t-bill rate is currently 6%, while the expected rate of return of the s& p 500 index is 12%. the standard deviation of portfolio a is 10% annually, while that of b is 31%, and that of the index is 20%. a. if you currently hold a market index portfolio, what would be the alpha for portfolios a and b? (negative values should be indicated by a minus sign. do not round intermediate calculations. round your answers to 1 decimal place.)