Updated: 31 July 2010
Use GEOMETRICP to calculate the cumulative distribution function of the geometric distribution.
The formula for the cumulative distribution function is:
SELECT [wctStatistics].[wct].[GEOMETRICP] (
is the number of failures. @X is an expression of type float or of a type that implicitly converts to float.
is the probability of success. @P is an expression of type float or of a type that implicitly converts to float.
· @X must be greater than or equal to zero (@X ≥ 0).
· @P must be greater than zero and less than or equal to one (0 < @P ≤ 1).
· For the probability mass function, use GEOMETRIC.
· For the upper cumulative distribution use 1 – GEOMTRICP(@X-1, @P).
Calculate the cumulative distribution function:
This produces the following result
(1 row(s) affected)
You can use the SeriesInt function from the XLeratorDB/math library to generate a dataset which can be pasted into EXCEL to generate a graph of the cumulative distribution function.
,wct.GEOMETRICP(SeriesValue, 0.1) as [f(x,0.1)]
,wct.GEOMETRICP(SeriesValue, 0.3) as [f(x,0.3)]
,wct.GEOMETRICP(SeriesValue, 0.5) as [f(x,0.5)]
,wct.GEOMETRICP(SeriesValue, 0.7) as [f(x,0.7)]
,wct.GEOMETRICP(SeriesValue, 0.9) as [f(x,0.9)]
This is an EXCEL-generated graph of the results