Lay people are sometimes uncomfortable with z-scores for a couple reasons. First, they don't like negative numbers and anyone who has a raw score less than the mean has a negative z-score. Second, they are uncomfortable with a z-score of 0 being average. Explaining to a parent that her child did average on an achievement test and has a z-score of 0 can be difficult. For this reason z-scores are often converted to a scale where negative value are not possible.. IQ scores, SAT scores, and T scores are examples of z-scores that have been converted.
Would you like to comment?
Join Diigo for a free account, or sign in if you are already a member.