(Expected rate of return and risk) Summerville Inc. is considering an investment in one of two common stocks. Given the information in the popup window: which investment is better, based on the risk (as measured by the standard deviation) and return of each? a. The expected rate of retum for Stock Ais %. (Round to two decimal places) 1 X Data table (Click on the following icon in order to copy its contents into a spreadsheet.) COMMON STOCK A PROBABILITY RETURN 0.30 11% 0.40 16% 0.30 18% COMMON STOCK B PROBABILITY RETURN 0.20 6% 0.30 6% 0.30 15% 0.20 21%