Standard Deviation
Definition
Square root of variance — a measure of dispersion in the same units as the data. Captures "typical" distance from the mean.
Example
A class with test scores averaging 75 with SD 10 has most students between 65 and 85.
Square root of variance — a measure of dispersion in the same units as the data. Captures "typical" distance from the mean.
A class with test scores averaging 75 with SD 10 has most students between 65 and 85.