A set of final examination grades in an introductory statist

A set of final examination grades in an introductory statistics course was found to be normally distributed with a mean of 75 and a standard deviation of 7.

1. what is the probability that a student scored below 84 on this exam?

Solution

mean=75

sd=7

for x=84, z= (84-75)/7 =1.286

probability that a student scored below 84 = P(z<1.286) = 0.10