the average sales price of a single-family house in the U.S. is $235,500. you randomly select 12 single family houses. what is the probability that the mean sales price is more than $225,000? assume...

the average sales price of a single-family house in the U.S. is $235,500. you randomly select 12 single family houses. what is the probability that the mean sales price is more than $225,000? assume that the prices are normally distrubuted with a standard deviation of $50,000.