Bruce Leichtman is president of Leichtman Research Group, Inc. (LRG), which specializes in research and consulting on broadband, media, and entertainment industries. In a recent survey, the company determined the cost of extra high-definition (HD) gear needed to watch television in HD. The costs ranged from $5 a month for a set-top box to $200 for a new satellite receiver. The file entitled HDcosts contains a sample of the costs of the extras whose purchase is required to watch television in HD.

a. Produce a 95% confidence interval for the population mean cost of the extras whose purchase would be required to watch television in HD.

b. Calculate the margin of error for this experiment.

c. If you were to view the sample used in part a to be a pilot sample, how many additional data values would be required to produce a margin of error of 5?

Assume the population standard deviation is 50.353.