This post will explain what z-scores are and how to calculate them in HSC Standard Math.

### What are ‘z-scores’?

A **z-score** is a statistical measure of how many standard deviations a raw score is above or below a mean. They are used to compare scores in a normal distribution. For instance, a z-score of 0 means it is equal to the mean, a z-score of 1 means its one standard deviation above the mean and a z-score of -1 means it is 1 standard deviation below the mean. The higher or lower the z-score, the further it is from the mean.

### How to calculate z-scores

The following video introduces z-scores and how to calculate them.