You can put this solution on YOUR website!
With the sample mean in Problem 9, find (a) the 95% confidence interval and (b) the 99% confidence interval.
I don't have the text but, if your sample mean is x-bar,
a) the 95% CI is x-bar-1.96[sigma/sqrt(n)] < mu < x-bar+1.96[sigma/sqrt(n)]
b) the 99% CI uses 2.576 in place of 1.96