The standard deviation of the amount of time devoted to movie previews was 4 minutes. Use that as a planning value for the standard deviation in answering the following questions.

1.If we want to estimate the population mean time for previews at movie theaters with a margin of error of 75 seconds, what sample size should be used? Assume 95% confidence.

2.If we want to estimate the population mean time for previews at movie theaters with a margin of error of 1 minute, what sample size should be used? Assume 95% confidence.