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

Answer:

8.08 %

Step-by-step 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 :

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

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

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

$=0.0808$

$=8.08%$

Answer : $8.08 %$