Understanding z-scores

Z-scores, sometimes called standard scores, have a very specific purpose, and for once, no one is debating it. The purpose of a z-score is to compare a single value to a normal distribution. More specifically, a z-score reports how many standard deviations your chosen value is from the mean.

Important note

You will not be asked to calculate a z-score for the exam. You will simply have to understand the purpose of it and identify when it is appropriate to use. That said, it is simpler than a lot of the things you have already learned to calculate, and practicing with it will help reinforce it in your memory.

This has many uses. Z-scores are often used for things such as percentiles, but let’s take a broader view. Any time you want to compare a single value to a dataset, the z-score is a good choice. Is this price too high? Is this weight too low? How do my grades compare to the other applicants? Can we market to this age bracket?

There are countless...