You want to estimate the proportion of gas stations in the state that have stopped accepting cash.

Question:

You want to estimate the proportion of gas stations in the state that have stopped accepting cash. You take a simple random sample of 150 stations. Twelve stations in the sample indicate that they have stopped accepting cash.
a. Build a 95% interval estimate of the overall station proportion based on your sample findings.
b. Build a 99% interval estimate of the overall station proportion based on your sample findings.