Twelve different video games showing substance use were observed and the duration times of game play (in seconds) are listed below (based on data from "Content and Ratings of Teen-Rated Video Games," by Haninger and Thompson, Journal of the American Medical Association, Vol. 291, No. 7). The design of the study justifies the assumption that the sample can be treated as a simple random sample. 4049 3884 3859 4027 4318 4813 4657 4033 5004 4823 4334 4317
a. Use the sample data to construct a 95% confidence interval estimate of ?, the mean duration of game play.
b. Use the sample data to construct a 99% confidence interval estimate of ?, the standard deviation of the duration times of game play.