The Center for Urban Transportation Research released a report stating that the average commuting distance in the United States is 10.9 mi (USA Today, August 13, 1991). Suppose that this average is actually the mean of a random sample of 300 commuters and that the sample standard deviation is 6.2 mi. Estimate the true mean commuting distance using a 99% confidence interval.

Weeks 7 & 8 Normal Distribution “The bell Shaped Curve”: describes the shape for some quantitative, continuous random variables Has two parameters: o = mean determines the location. o = standard deviation determines spread, variation, scatter. The “area” under the curve within a range of X values is equal to proportion of the population within that range of X values