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 2.4 gallons. The mean water usage per family was found to be 19.5 gallons per day for a sample of 3034 families. Construct the 98% confidence interval for the mean usage of water. Round your answers to one decimal place.

Answer 1

The confidence interval for the mean usage of water is (18.7,20.5).

Given population standard deviation of 2.4, mean of 19.5 gallons per day and confidence interval of 98%.

We have to find the confidence interval for the mean usage of water.

To find out the confidence interval we have to first find margin of error.

μ=19.5

σ=2.4

α=0.98

α/2=0.49

We have to find the z value for the p value 0.49 which is z=2.33

Margin of error=z*μ/$\sqrt{n}$

=2.33*19.5/$\sqrt{3034}$

=0.82

lower level=mean -m

=19.5-0.82

=18.68

after rounding upto 1 decimal

=18.7

upper mean = mean+m

=19.5+0.82

=20.52

Hence the confidence interval for the usage of water is (18.7,20.52).

Learn more about margin of error at brainly.com/question/10218601

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