A human resource manager for Carver County is evaluating a recent effort to improve the health ...

     A human   resource manager for Carver County is evaluating a recent effort to improve   the health of the county’s firefighters by providing an exercise room in each   of the county’s firehouses. Their   records prior to installing the exercise rooms indicate that the mean weight   of all county firefighters is 198 pounds with a standard deviation of 13   pounds. A random sample of 40   firefighters taken six months after the program was implemented revealed that   the mean of the sample was 192 pounds. Construct a 96% confidence interval for the mean weight of all   firefighters six months after the exercise rooms were installed. Assume that σ has not changed. Does it appear that the program is   working?