PredictStdev (DMX)

适用于: SQL Server Analysis Services

返回指定列的预测标准偏差。

语法

  
PredictStdev(<scalar column reference>)  

应用于

标量列。

返回类型

标量列引用>指定的<类型的标量值。

注解

如果列引用是离散的, 则 PredictStdev 返回 0,因为无法从离散值计算标准偏差。

示例

以下示例根据 TM Decision Tree 挖掘模型,使用自然预测联接确定某个人是否可能购买自行车,并且还确定该预测的标准偏差。

SELECT  
  [Bike Buyer],  
  PredictStdev([Bike Buyer]) AS [Standard Deviation]  
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  

另请参阅

数据挖掘扩展插件 (DMX) 函数参考
函数 (DMX)
通用预测函数 (DMX)