f.use the daily returns from c. to calculate rolling annual returns for the three stocks, the portfolio and djia the following two ways •use a for loop to perform the task by looping through 252 daily data points each time and saving the results into a new variable •use the rolling function with a time window of 252 days (e.g., variable.rolling().mean() with da being the data) •are the results the same from the two steps?