math - Please help me to understand
posted by Jennifer on .
The average selling price of homes in a certain city is $356,300. Assume the variable is normally distributed with a standard deviation of $64,600. If 396 homes are for sale, how many homes will sell for more than $325,000? (Round up to the next whole number.)
I don't understand how to do this problem. I have a test this weekend and want to understand. It won't be the same question, but one similar. Thanks.
I don't know if you are using some kind of chart for the normal distribution or if you have a "fancy" calculator that can handle that.
The method used by calculators varies from model to model, so I cannot describe it
change your 325000 to a z-score
z-score for 325000 = (325000-356000)/64600
If you have a table, find -.48 (the best you can probably do on the chart) to find .3156
So the prob that the house will cost MORE than 325000 is
1 - .3156 or .6844
so number sold at that range is .6844(396) or 271 homes