Updated: 9 August 2010
Use GAMMADIST to calculate the gamma distribution. The formula for the probability density function of the gamma distribution is:
And the cumulative distribution function is the incomplete gamma function
Syntax
SELECT [wctStatistics].[wct].[GAMMADIST] (
<@X, float,>
,<@Alpha, float,>
,<@BETA, float,>
,<@Cumulative, bit,>)
Arguments
@X
is the value at which you want to evaluate the distribution. @X is an expression of type float or of a type that can be implicitly converted to float.
@Alpha
is the alpha parameter to the distribution. @Alpha is an expression of type float or of a type that can be implicitly converted to float.
@BETA
is the beta parameter to the distribution. @BETA is an expression of type float or of a type that can be implicitly converted to float.
@Cumulative
is a logical value that determines if the probability density function (False, 0) or the cumulative distribution function (True, 1) is being calculated.
Return Types
float
Remarks
· If @X < 0, GAMMADIST will return an error
· If @Alpha ≤ 0 or @BETA ≤ 0, GAMMADIST will return an error.
Examples
select wct.GAMMADIST(10.00001131,9,2,'False')
This produces the following result
----------------------
0.032639130418294
(1 row(s) affected)
select wct.GAMMADIST(10.00001131,9,2,'True')
This produces the following result
----------------------
0.0680940037098249
(1 row(s) affected)
select wct.GAMMAP(9,10.00001131/2)
This produces the following result
----------------------
0.0680940037098249
(1 row(s) affected)
See Also