Statistics
posted by Anonymous .
The mean monthly rent for a onebedroom apartment without a doorman in Manhattan is $2,636. Assume the standard deviation is $500. A real estate firm samples 100 apartments. What is the probability that the average rent of the sample is more than $2,680?

Assuming a normal distribution:
Z = (scoremean)/SEm
SEm = SD/√n = 500/√100 = 500/10 = 50
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.