Question

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

Answer 1

8.08 %

Explanation:

Let us denote :
`X=` 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 %`