Question

the graph represents the distribution of the number of questions answered correctly on a 50-question math test.
math test scores
what is the standard deviation of the data?
○ 4
○ 8
○ 12
○ 24

Explanation:

Step1: Identify mean of normal curve

The peak of the normal distribution (the highest point of the curve) is at $x=36$, so this is the mean $\mu = 36$.

Step2: Find 1 standard deviation from mean

In a normal distribution, the data is within 1 standard deviation of the mean at the points where the curve transitions from curving upward to downward (the inflection points). These points align with $x=32$ and $x=40$.
Calculate the difference between the mean and one of these points: $\sigma = |36 - 32| = 4$

Answer:

A. 4