好難的maths question

In a press conference, the CEO of a financial corporation states that the
average gain per stock of the stock market for the last six months is 3%.
However, a stock analyst believes that the CEO’s statement is not true.
Accordingly, he selects a random sample of ten stocks and finds that the
mean and the standard deviation of the percentages of gains for the last
six months of these stocks are 2.77 and 3.9189 respectively. Assuming
that the percentage of gains may be approximated by a normal
distribution,
a is this opposed to the CEO’s statement at 0.05 level of significance?
(Do not use the p-value approach).
b use a p-value approach to test the corresponding hypothesis.