# Covariance Functions

Covariance functions return the statistical covariance - how much two sets of values change together based on a sample of the population (COVAR), or based on a biased population (COVARP).

Covariance measures how two sets of values vary together. This elementary function is used as a building block for some of the two-dimensional statistical functions used in linear regression, as it describes collectively how the two sets of values vary around their mean values.

- COVAR (
*numeric1*,*numeric2*)

- where
*numeric1*and*numeric2*are facts or metrics - Computes the product of variance from mean for each value of
*x*and*y*. These values are summed and then divided by*(n*]. - Use for sets of values that are only a sample of the total (biased) population.

- where

- COVARP (
*numeric1*,*numeric2*)- where
*numeric1*and*numeric2*are facts or metrics - Use covarp for calculating covariances when the numeric values are the entire population of values.
- Use for sets of values that include the entire (unbiased) population, use COVARP.

- where

**Syntax**

```
SELECT COVAR(…)
SELECT COVAR(metric1, metric2)
SELECT COVAR(fact1, metric2)
SELECT COVAR(fact1, fact2)
SELECT COVARP(metric1, metric2)
SELECT COVARP(fact1, metric2)
SELECT COVARP(fact1, fact2)
```

**Examples**

```
SELECT COVAR(Total Cost of Inputs, Gross Margin)
SELECT COVARP(Height, Weight)
```

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