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PredictVariance (DMX)

  • Artikkeli

Applies to: SQL Server Analysis Services

Returns the variance of a specified column.

Syntax

  
PredictVariance(<scalar column reference>)

Applies To

A scalar column.

Return Type

A scalar value of the type that is specified by <scalar column reference>.

Remarks

If the column reference is discrete, PredictVariance returns 0 because the variance cannot be calculated from discrete values.

Examples

The following example uses a natural prediction join to determine if an individual is likely to be a bike buyer based on the TM Decision Tree mining model, and also determines the variance for the prediction.

SELECT  
  [Bike Buyer],  
  PredictVariance([Bike Buyer]) AS [Variance]  
FROM  
  [TM Decision Tree]  
NATURAL PREDICTION JOIN  
(SELECT 28 AS [Age],  
  '2-5 Miles' AS [Commute Distance],  
  'Graduate Degree' AS [Education],  
  0 AS [Number Cars Owned],  
  0 AS [Number Children At Home]) AS t

See Also

Data Mining Extensions (DMX) Function Reference
Functions (DMX)
General Prediction Functions (DMX)