Bruce Leichtman is president of Leichtman Research Group, Inc. (LRG), which specializes in research and consulting on broadband, media, and entertainment industries. In a survey, the company determined the cost of HDMI Digital Antenna systems ranged from about $25 to $200 (source: “Everything you need to know about replacing cable with an HDTV antenna,”

www.fool.com, June 27, 2015). The file titled HDcosts contains a sample of the total costs including installation for HDMI Digital Antenna systems required to watch television in HD.

a. Produce a 95% confidence interval for the population mean cost of the purchases 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 as 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.