skewness_y() | skewness_x()

Since 1.3.0

Calculate the skewness from a two-dimensional statistical aggregate for the given dimension. For example, skewness_y() calculates the skewness for all the values of the y variable, independent of values of the x variable. The skewness is the third statistical moment. It is a measure of asymmetry in a data distribution.

Samples

Calculate the skewness of a sample containing the integers from 0 to 100:

SELECT skewness_x(stats_agg(data, data))
  FROM generate_series(0, 100) data;

skewness_x
----------
0

Arguments

The syntax is:

skewness_y(
  summary StatsSummary2D,
  [ method TEXT ]
) RETURNS DOUBLE PRECISION

skewness_x(
  summary StatsSummary2D,
  [ method TEXT ]
) RETURNS DOUBLE PRECISION

Name	Type	Default	Required	Description
summary	StatsSummary2D	-	✔	The statistical aggregate produced by a stats_agg call
method	TEXT	sample	-	The method used for calculating the skewness. The two options are population and sample, which can be abbreviated to pop or samp

Returns

Column	Type	Description
skewness_y	skewness_x	DOUBLE PRECISION