Question

if the mean is 300 and the standard deviation is 100, a score of 250 would equal a z-score of ______.

a -0.5

b -0.6

c 0.5

d 0.6

Explanation:

Step1: Recall z - score formula

The formula for calculating the z - score is $z=\frac{x-\mu}{\sigma}$, where $x$ is the raw score, $\mu$ is the mean, and $\sigma$ is the standard deviation.

Step2: Identify values

We are given that $x = 250$, $\mu=300$, and $\sigma = 100$.

Step3: Substitute values into formula

Substitute the values into the formula: $z=\frac{250 - 300}{100}=\frac{- 50}{100}=-0.5$

Answer:

a. -0.5