You found a 99% confidence interval of $2.03 million to $2.51 million for the mean gross earnings of all Rolling Stones concerts.

a. Determine the margin of error, E.

b. Explain the meaning of E in this context in terms of the accuracy of the estimate.

c. Find the sample size required to have a margin of error of 12 mont and a 95% confidence level.

d. Obtain a 95% confidence interval for the mean gross earnings if a sample of the size determined in part (c) has a mean of $2.35 million.