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;
Z-score, z = (128 - 70)/(20)
Z-score, z = 58/20
Z-score, z = 2.9
Read more on z-scores here: brainly.com/question/26714379
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