Question

At a local restaurant, the amount of time that customers have to wait for their food is normally distributed with a mean of 24 minutes and a standard deviation of 3 minutes. What is the probability that a randomly selected customer will have to wait less than 25 minutes, to the nearest thousandth?

Answer 1

25 min is 1/3 s.d. above the mean ... z-score of .333...

use a z-score table to find the portion of the population
... below a 1/3 z-score