Question

The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. Assume that the population standard deviation is 2.3 gallons. The mean water usage per family was found to be 16.7 gallons per day for a sample of 784 families. Construct the 95% confidence interval for the mean usage of water. Round your answers to one decimal place.

Lower endpoint:

Upper endpoint:

Answer 1

given data are:-

sample mean () = 16.7

population sd () = 2.3

sample size (n) = 784

z critical value for 95% confidence level, both tailed test be:-

the 95% confidence interval be:-

lower endpoint = 16.5

upper endpoint = 16.9

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