BETADIST

BETADIST(x, alpha, beta [,A] [,B])

Returns the cumulative probability function for a beta distribution (only cumulative).

x	The number between A and B from the distribution.
alpha	The first parameter to the distribution.
beta	The second parameter to the distribution.
A	(Optional) The lower bound to the interval of x.
B	(Optional) The upper bound to the interval of x.

REMARKS

* This function is only available for backwards compatibility and should not be used.
* BETA.DIST was added in Excel 2010 to replace this function and adds an additional parameter.
* The beta distribution is a continuous distribution
* This function always returns the cumulative probability function. There is no option for the probability distribution function.
* If "x" < "A", then #NUM! is returned.
* If "x" > "B", then #NUM! is returned.
* If "alpha" = 0, then #NUM! is returned.
* If "beta" = 0, then #NUM! is returned.
* If "A" = "B", then #NUM! is returned.
* If "A" is left blank, then A = 0.
* If "B" is left blank, then #NUM! is returned.
* If any of the arguments are not numeric, then #VALUE! is returned.
* You can use the BETA.INV function to return the inverse of the probability distribution function for a beta distribution.
* This is similar to the HYPGEOMDIST and LOGNORMDIST functions.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=BETADIST(2, 8, 10, 1, 3) = 0.685
2	=BETADIST(-2, 8, 10, -5, 3) = 0.282
3	=BETADIST(3, 1, 1, 2, 3) = 1
4	=BETADIST(3, 1, 1, , 3) = 1
5	=BETADIST(3, -1, 1, 2, 2) = #NUM!
6	=BETADIST(3, 1, 1, 2, ) = #NUM!
7	=BETADIST(3, 1, -1, 2, 2) = #NUM!
8	=BETADIST(3, 1, 1, 2, 2) = #NUM!
9	=BETADIST(3, 1, 1, 2, "some text") = #VALUE!