Z scores

A Z score is a number obtained by dividing a deviation score by the standard deviation.

A Z score is a raw score converted into standard deviation units.

Given a mean score of 80 and a standard deviation of 5, convert a raw score of 85 into a Z score.

This means that a raw score of 85 is 1 standard deviation unit (5 points)above the mean of 80.

A student scored 70 on a statistics test that had a mean of 85 and a standard deviation of 10. Convert the students raw score into a Z score.

This means that the students raw score of 70 is 1.5 standard deviation units
(10 points) below the mean.