A taxi company is interested in the amount of time its vehicles are out of operation for repair. Find a 95% confidence interval for the mean number of days in a month that all taxis are out of operation for repair. A random sample of nine taxis had the following number of days that each was in repair (Note that we are using sample data and must estimate the sample standard deviation using the sample formula.):
10 16 19 14 19 21 22 8 17