Question

The scores on a test given to all juniors in a school district are normally distributed with a mean of 75 and a standard deviation of 7.
Find the percent of juniors whose score is no more than 89.

The percent of juniors whose score is 89 or below is ___%

Answer 1

$\mathbb P(X\le89)=\mathbb P\left(\dfrac{X-75}7\le\dfrac{89-75}7\right)=\mathbb P(Z\le2)\approx0.9773=97.73\%$