Question

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

b)A 99% confidence interval is desired for the mean amount of beef consumed.

PLEASE SHOW IN EXCEL

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.

Answer 1

a) The margin of error is . Thus,

For ,

b)For ,

c) The margin of error is .

Here the sample proportion of Americans who over-consume red meat is not given. Hence sample size cannot be calculated.

Provide required data.