posted by Anonymous .
The average commute time via train from the chicago O'Hare Airport to downtown is 60 minutes with a s=15 minutes.Assume that the commute times are normally distributed. what proportion of commutes would be:
a. Longer than 80 minutes?
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.