Returns the skewness of the distribution of value_expression.
This function returns the REAL data type.
To invoke the time series version of this function, use the GROUP BY TIME clause. For more information, see Teradata Vantage™ - Time Series Tables and Operations, B035-1208.
Skewness
Skewness is the third moment of a distribution. It is a measure of the asymmetry of the distribution about its mean compared with the normal, Gaussian, distribution.
The normal distribution has a skewness of 0.
Positive skewness indicates a distribution having an asymmetric tail extending toward more positive values, while negative skewness indicates an asymmetric tail extending toward more negative values.
Computation
The equation for computing SKEW is defined as follows:
where:
| This variable … | Represents … |
|---|---|
| x | value_expression |
Conditions That Produce a Null Result
- Fewer than three non-null data points in the data used for the computation
- STDDEV_SAMP(x) = 0
- Division by zero