During a routine check of the fluoride content of gotham city's water supply, the given results were obtained from replicate analyses of a single sample: 0.90900 mg/l , 0.88900 mg/l , 0.91300 mg/l , 0.88700 mg/l , and 0.91900 mg/l . determine the mean and 90% confidence interval for the average fluoride concentration in this sample. report the mean and the confidence interval with three significant figures.

mean:

90% confidence interval: