The time required to make 900 gallons of synthetic rubber at a plant in South America in a recent year was normally distributed with a mean of 15 hours and a standard deviation of 2.5 hours. What is the probability that it will take more than 17 hours to make 900 gallons of synthetic rubber?

Answer 1

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 that Z score.