A fitness center is interested in finding a 98% confidence interval for the mean number of days per week that Americans

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A fitness center is interested in finding a 98% 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 257 members were looked at and their mean number of visits per
week was 3.2 and the standard deviation was 1.7. Round answers to 3
decimal places where possible.
a. To compute the confidence interval use
a ? t z distribution.
b. With 98% confidence the population mean number of visits
per week is between and visits.
c. If many groups of 257 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.