A courier service company has found that their delivery time of parcels to clients is normally distributed with a mean of 22 minutes and a standard Deviation of 4 minutes. What is the probability that a randomly selected parcel will take less than 13 minutes to deliver to the client?
Z = (score-mean)/SD
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.