A stockbroker who wants to compare mean returns and risk

Question

Question: A stockbroker who wants to compare mean returns and risk (measured by variance) of two stocks and gets the following results:

First stock                    Second stock

N1 = 31                           N2 = 31

1 = 0.45                          2 = 0.35

S1 = 0.60                      S2 = 0.40

Are there any significant differences in the mean returns and risks? (Assume that daily price changes are normally distributed.)