Your stock investments returned 8%, 12%, and-4% in consecutive years What is the arithmetic mean return?(Round your answer to 2 decimal places) What is the standard deviation of these returns? (Round your answer to a decimal places) Assume a normal probability distribution. Based on the arithmetic mean and standard deviation calculated above, what Rx is the range of returns you expect to see 68% of the time? what is the probability of losing 3n; or more (i.e. return is-3% or lower)