ACT scores are normally distributed and from 2015 to 2017, the mean was 20.9 with a standard deviation of 5.6. A perfect score is 36. What percentage of the testers scored a perfect score?

Question 4 options:

0.46%

0.35%

99.65%

99.64%

A

Step-by-step explanation:

36 - 20.9 = 15.1

standard deviation = 5.6

15.1/5.6 = 2.696 (428571)

So 2.7 times the standard deviation of people have a perfect score.

(which is a little less then 3 times the standard deviation)

This accounts for the population of the top 0.46 %