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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)
If a row contains a missing or null value, it is not factored into the calculation.
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.
For a version of this function computed over a rolling window of rows, see ROLLINGVAR Function.
| D lang syntax |
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| RawWrangle | true |
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| Type | ref |
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| showNote | true |
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| WrangleText | pivot value:var(myRating) group:postal_code limit:1 |
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var(myRating) |
Output: Returns the variance of the group of values from the myRating column.
| D lang syntax |
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| RawWrangle | true |
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| Type | syntax |
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| showNote | true |
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| WrangleText | pivot value:var(function_col_ref) [group:group_col_ref] [limit:limit_count] |
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var(function_col_ref) [group:group_col_ref] [limit:limit_count] |
| Argument | Required? | Data Type | Description |
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| function_col_ref | Y | string | Name of column to which to apply the function |
For more information on the group and limit parameters, see Pivot Transform.
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.
| Required? | Data Type | Example Value |
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| Yes | String (column reference) | myValues |
| Include Page |
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| EXAMPLE - Statistical Functions |
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| EXAMPLE - Statistical Functions |
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