Assume stock As recent 5-year return is 8%, 5%, -2%, 6% and 3%. What is the standard error of stock A using the information in the past 5 years?

Follow up question: now there is another stock, stock B, that has an expected return of 4.60% and a standard deviation of 3.20%.

Which one would you prefer?

Follow up question: now there is another stock, stock C, that has an expected return of 5.20% and a standard deviation of 4.75%.

Among stock A and stock C, which one would you prefer?