This video covers how to calculate z-score in a few different situations. Sometimes you're given a whole list of numbers, while other times you get a word problem that tells you the mean and standard deviation and asks you to find the z-score of a particular data point.
Z-Score Rule For Outliers
In stats they give you lots of different criteria for when a data point or measurement is "out there" enough to ignore (I meant "to call it an outlier so it's okay to ignore it"). This video considers yet another: z-scores!
Z-Score As Measure of Unusualness
There are lots of ways to determine outliers, but z-score introduces yet another category altogether: usual vs unusual. It's kind of in the middle between being "usual" and being an "outlier".
Z-score vs Coefficient of Variation
If your class covers coefficients of variation, there can be a bit of confusion as to how that's different from z-score. Well, it turns out one is for comparing categories -- think apples and watermelons -- as opposed to individual pieces of data.
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)