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D toc

Excerpt

Computes the variance among all values in a column. Input column can be of Integer or Decimal. If no numeric values are detected in the input column, the function returns `0`

The variance of a set of values attempts to measure the spread in values around the mean. A variance of zero means that all values are the same, and a small variance means that the values are closely bunched together. A high value for variance indicates that the numbers are spread out widely. Variance is always a positive value.

Var(X) = [Sum ((X - mean(X))2)] / Count(X)

Variance comes in two flavors: population variance and sample variance.

• Population variance computes the variance from all possible values.
• Sample variance computes from a subset or sample of all values.
• Since
D s product
r true
has access to all available values, the computation for population variance is used across the entire dataset.

The square root of variance is standard deviation, which is used to measure variance under the assumption of a bell curve distribution. See STDEV Function.

If a row contains a missing or null value, it is not factored into the calculation.

For a version of this function computed over a rolling window of rows, see ROLLINGVAR Function.

D s
snippet Basic

D code

pivot value:VAR(myRating) group:postal_code limit:1

Output: Generates a new table containing the unique values of the `postal_code` column and the variance of the group of values from the `myRating` column for the `postal_code` value. The `limit` parameter defines the maximum number of output columns.

D s
snippet Syntax

D code

pivot value:VAR(function_col_ref) [group:group_col_ref] [limit:limit_count]

ArgumentRequired?Data TypeDescription
function_col_refYstringName of column to which to apply the function

For more information on the `group` and `limit` parameters, see Pivot Transform.

D s lang notes

### function_col_ref

Name of the column the values of which you want to calculate the variance. Column must contain Integer or Decimal values.

• Literal values are not supported as inputs.
• Multiple columns and wildcards are not supported.

D s
snippet usage

Required?Data TypeExample Value
YesString (column reference)`myValues`

D s
snippet Examples

Include Page
 EXAMPLE - Statistical Functions EXAMPLE - Statistical Functions

D s also
label aggregate