Updated: 9 August 2010
Use BETADIST to calculate the beta cumulative probability density function. 
 
Where 
Bx(α,β) is the incomplete beta function and 
Ix(α,β) is the regularized incomplete beta function.
Syntax
SELECT [wctStatistics].[wct].[BETADIST] (
   <@X, float,>
 ,<@P, float,>
 ,<@Q, float,>
 ,<@A, float,>
 ,<@B, float,>)
Arguments
@X
is any real number. @X is an expression of type float or of a type that can be implicitly converted to float. @X is the value between @P and @Q at which to evaluate the function
@P
is any real number. @P is an expression of type float or of a type that can be implicitly converted to float. @A is a parameter to the distribution
@Q
is any real number. @Q is an expression of type float or of a type that can be implicitly converted to float. @Q is a parameter to the distribution
@A
is any real number. @A is an expression of type float or of a type that can be implicitly converted to float. @A is the lower bound to the distribution. If you enter NULL, @A defaults to zero
@B
is any real number. @B is an expression of type float or of a type that can be implicitly converted to float.   @B is the upper bound to the distribution. If you enter NULL @B defaults to to zero.
 
Return Types
float
Remarks
·         If @X ≤ 0, BETADIST will return an error.
·         If @P ≤ 0 or @Q ≤ 0, BETADIST will return an error
·         If @X< @A or @X > @B or @A = @B, BETADIST will return an error.
·         If you enter NULL for @A and @B, BETADIST will use zero and one. 
Examples
select wct.BETADIST(7,5,10,6,8)
This produces the following result
----------------------
0.91021728515625
 
(1 row(s) affected)