Mathematics
Z-Score (Standard Score)
Quick fact
A z-score of 0 means the value is exactly average; a z-score of 2 means it's two standard deviations above the mean, placing it in the top 2.5% of a normal distribution (assuming normality).
Why this is interesting
Have you ever wondered how unusual your test score really is compared to the rest of the class? The z-score is the universal ruler that measures exactly that—turning any score into a simple, comparable number.