Interpret the Area under the Standard Normal Curve as a Probability
-Scores on a standardized test are normally distributed with a mean of 104 and a standard deviation of 20 . An individual's test score is found to be 109 . Find the $\mathrm { z }$-score corresponding to this value.
A) $0.25$
B) $- 0.25$
C) $4.00$
D) $- 4.00$

Question

Quizplus · Accepted Answer

The z-score is calculated using the formula $z = \frac{(X - \mu)}{\sigma}$, where $X$ is the value in question, $\mu$ is the mean, and $\sigma$ is the standard deviation. Plugging in the given values, $z = \frac{(109 - 104)}{20} = \frac{5}{20} = 0.25$.

Interpret the Area Under the Standard Normal Curve as a Probability