Consider the following rates:

Year Large Company Stocks US Treasury Bills

1 3.98% 4.56%

2 14.33 4.92

3 19.17 3.84

4 -14.51 6.98

5 -32.00 5.22

637.41 5.36

A. Calculate the arithmetic average returns for large-company stocks and T-bills over this period

Avg. Returns

Large Company Stock 7.59?

T-bills 3.87

B. Calculate the standard deviation of the returns for large-company stocks and T-bills over this period

Standard Deviation

Large-company stocks 4.72

T-bills 3.31?

Where am I off on these? What equations would I use to find these numbers?