Use Modern Approach:
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 within ±0.05.
D.) Find the sample size needed for a 99% confidence interval to specify the proportion within ±0.05.