The z-score of a person who scored 128 on the exam is equal to 2.9
<h3>What is a z-score?</h3>
A z-score is also referred to as a z-value or standard score and it can be defined as a measure of the distance between a raw score and the mean, when standard deviation units are used.
Mathematically, the z-score of a given sample score in a normal distribution can be calculated by using this formula:
Where:
x represents the sample score.
u represents the mean score.
σ represents the standard deviation.
Substituting the given parameters into the formula, we have;