In a random sample of 44 downloadable books from a website, the mean cost is $8.58 with a standard deviation of $2.09. Which interval is the 95% confidence interval for the mean cost oof all the downloadable books on the website?
($7.77,$9.35)
($7.96, $9.20)
($8.26, $8.90)
($8.39, $8.77)