The number of wins in a season for 32 randomly selected professional football teams arelisted below. Construct a 90% confidence interval for the true mean number of wins in a season. Mean(x) = sum of 32 observations / 32 = 7.97

Standard deviation( sd )=2.62

Sample Size(n)=32

Confidence Interval = [ 7.97 ± Z a/2 ( 2.62/ Sqrt ( 32) ) ] = [ 7.97 - 1.64 * (0.4632) , 7.97 + 1.64 * (0.4632) ] = [ 7.2,8.7 . What are the steps used to solve this? How did they find their Standard Deviation? Also what does the Z stand for in the confidence interval?