The average score of this quiz is 24 points with a standard deviation of 1.5 points. What is the probability that someone scored 21.9 or less

Question

asked Feb 9, 2021 225k views

1 Answer

Lesmana · Answer 1 · 2021-02-15T16:41:05+0000

Answer:

8.08 %

Explanation:

Let us denote :
score X follows a normal distribution with mean
=24 and standard deviation
=1.5

Step 2

The probability that someone scored 21.9 or less is :

$\mathrm{P}(\mathrm{X} \leq 21.9)$

$=\mathrm{P}\left(\mathrm{Z} \leq (21.9-24)/(1.5)\right)$

$=\mathrm{P}(\mathrm{Z} \leq-1.4)$

=0.0808

=8.08%

Answer :
8.08 %