Rates of return (annualized) in two investment portfolios are compared over the last 12 quarters. They are considered similar in safety, but portfolio Bis advertised as being \"less volatile." {a} At a = .025, does the sample show that portfolio A has signicantly greater variance in rates of return than portfolio 3? {b} At a = .025, is there a signicant difference in the means? Portfolio A Portfolio B 5.23 9.07 11.65 3.53 12.59 7.59 4.14 6.49 5.56 7.50 8.77 7.08 7.87 7.51 9.85 7.86 9.55 3.64 4.89 3.85 11.63 7.64 11.34 9.86 \f\f