Problem 12-9 Calculating Returns and Variability (L01) You've observed the following returns on Regina Computer's stock over the past five years: 16%. -16%, 18%, 28%, and 10% a. What was the arithmetic average return on Regina's stock over this five-year perlod? (Round the final answer to 1 decimal place) Average return b-1. What was the variance pof Regina's returns over this period? (Do not round intermediate calculations, Round the final answer to 5 decimal places.) Variance b-2. What was the standard deviation of Regina's returns over this period? (Do not round intermediate calculations. Round the final answer to 1 decimal place.) Standard deviation