Variance is a very important statistical measure that shows how much certain items are scattered on a numerical axis. Mathematically, it follows this formula:
The preceding formula is for the variance over the whole of a statistical population, and the following formula is for the variance over a sample of a statistical population:
What do the letters in the preceding formulas mean?
- N is the number of items in a dataset
- i is an item index
- xi is the value of a certain item
- X is a mean
Both formulas are implemented in SQL Server. ...
