Using the three-year return percentage variable in Retirement Funds: a. Construct a table that computes the mean for each combination of market cap, risk, and rating. b. Construct a table that computes the standard deviation for each combination of market cap, risk, and rating. c. What conclusions can you reach concerning differences based on the market cap (small, mid-cap, and large), risk (low, average, and high), and rating (one, two, three, four, and five)?