Question

Cristina scored an 87 on her general psychology exam and wants to know how she did relative to

her other exams, but she hasn't gotten her scores back on those yet. The class average for the
general psychology exam was 84 with a standard deviation of 2.5. Calculate a z score for the score
so she can compare it to the z-scores of the other exams when they are graded.

Answer 1

A z-score is a measure of how many standard deviations a value is away from the mean of a distribution. To calculate a z-score for Cristina's score, we can use the formula:

z = (x - μ) / σ

where x is the value, μ is the mean, and σ is the standard deviation. Plugging in the numbers, we get:

z = (87 - 84) / 2.5

z = 1.2

This means that Cristina's score is 1.2 standard deviations above the mean. When she gets her scores back on the other exams, she can compare the z-scores to see which one she did relatively better or worse on.