The time for a professor to grade a student’s homework in statistics is normally distributed with a mean of 12.8 minutes and a standard deviation of 2.1 minutes. What is the probability that randomly...

The time for a professor to grade a student’s homework in statistics is normally distributed with a mean of 12.8 minutes and a standard deviation of 2.1 minutes. What is the probability that randomly selected homework will require less than 18 minutes to grade?