ANSWER: Answer will include that a z-score is a number (a standard score) that tells how many standard deviations above or below the mean score is. To convert an original score to a z-score, we subtract the mean from the score. The resulting number is then divided by the standard deviation for the group of scores. To illustrate, Abby had a score of 75 on the test with a mean of 70 and a standard deviation of 5. Therefore, 75 minus 70 equals 5, which is divided by the standard deviation of 5 and equals 1. So, Abby’s
z-score is +1.0, which means her test score of 75 is one standard deviation above the mean.