A fitness center is interested in finding a 90% confidence interval for the mean number of days per week that Americans who are members of a fitness club go to their fitness center. Records of 266 members were looked at and their mean number of visits per week was 3.1 and the standard deviation was 2.9. a. To compute the confidence interval use a
?
distribution.

b. With 90% confidence the population mean number of visits per week is between
and
visits.

c. If many groups of 266 randomly selected members are studied, then a different confidence interval would be produced from each group. About
percent of these confidence intervals will contain the true population mean number of visits per week and about
percent will not contain the true population mean number of visits per week.