The U.S. Census Bureau announced that the median sales price of new houses sold in 2009 was $215,600, and the mean sales price was $270,100 www.census.gov/newhomesales, March 30, 2010). Assume that the standard deviation of the prices is $90,000.
If you select a random sample of n = 100, what is the probability that the sample mean will be between $275,000 and $290,000?