Question: During a recent drought, a water utility in a certain town sampled 100 residential water bills and found that 73 of the residences had reduced

During a recent drought, a water utility in a certain town sampled 100 residential water bills and found that 73 of the residences had reduced their water consumption over that of the previous year.

a. Find a 95% confidence interval for the proportion of residences that reduced their water consumption.

b. Find a 99% confidence interval for the proportion of residences that reduced their water consumption.

c. Find the sample size needed for a 95% confidence interval to specify the proportion to within ± 0.05.

d. Find the sample size needed for a 99% confidence interval to specify the proportion to within ± 0.05.

e. Someone claims that more than 70% of residences reduced their water consumption. With what level of confidence can this statement be made?

f. If 95% confidence intervals are computed for 200 towns, what is the probability that more than 192 of the confidence intervals cover the true proportions?

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a X 73 n 100 p 73 2100 4 072115 z 025 196 The confidence interval is 072115 1960721151 072115100 4 o... View full answer

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