The New York Times reported (L. J. Flynn, Tax Surfing, The New York Times, March 25, 2002, p. C10) that the mean time to download the home page for the Internal Revenue Service (IRS), www.irs.gov, was 0.8 second. Suppose that the download time was normally distributed, with a standard deviation of 0.2 second. If you select a random sample of 30 download times, what is the probability that the sample mean is less than 0.75 second? Please submit your calculation and specify which theorem/s you used.