Many medical professionals believe that eating too much red meat increases the risk of heart disease and cancer. Suppose you would like to conduct a survey to determine the annual consumption of beef by a typical American and want to use four pounds as the desired margin of error for a confidence interval of the population mean. Assume the population standard deviation is 20 pounds. Determine the sample size when:

A 90% confidence interval is desired for the mean amount of beef consumed.

B 99% confidence interval is desired for the mean amount of beef consumed.

Suppose you want to develop a confidence interval for the proportion of Americans who over-consume red meat with a desire margin of error of 0.1%. Determine the sample size needed when:

c) A 90% confidence interval is desired for the proportion of Americans who over-consume red meat.

d) A 95% confidence interval is desired for the proportion of Americans who over-consume red meat.