The Number of Wins in a Season for 32 Randomly $\sigma$

The number of wins in a season for 32 randomly selected professional football teams are listed below.
Construct a 90% confidence interval for the true mean number of wins in a season. Assume that $\sigma$ is 2.6.
$$\begin{array} { l l l l l l l l } 9 & 9 & 9 & 8 & 10 & 9 & 7 & 2 \\\\11 & 10 & 6 & 4 & 11 & 9 & 8 & 8 \\\\12 & 10 & 7 & 5 & 12 & 6 & 4 & 3 \\\\12 & 9 & 9 & 7 & 10 & 7 & 7 & 5\end{array}$$