need help with a-2 and b-2

Consider the following table for a period of six years a-1. Calculate the arithmetic average returns for large-company stocks and T-bills over this time period. (Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 3216.) 0.2. Calculate the standard deviation of the returns for large-company stocks and T-bills over this time period. (Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.) Calculate the observed nisk premium in each year for the large-company stocks versus the T.bills. b-1. What was the arahmetic average titk premitum over this period? (A negotive answer should be indicated by o minus sign. Do not round intermediate Calculate the observed risk premium in each year for the large-company stocks versus the T-bills. b-1. What was the arithmetic average risk premium over this period? (A negative answer should be indicated by a minus sign. Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b-2. What was the standard deviation of the risk premium over this period? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) Answer is complete but not entirely correct