MS Excel - Excel BETA.INV() function

Description

The BETA.INV() function is used to get the inverse of the beta cumulative probability density function (BETA.DIST).

If probability = BETA.DIST(x,...TRUE), then BETA.INV(probability,...) = x.

The beta distribution can be used in project planning to model probable completion times given an expected completion time and variability.

Version: Excel 2013

Syntax

BETA.INV(probability,alpha,beta,[A],[B])

Parameters

Name	Description	Data Type	Required/ Optional
Probability	A probability associated with the beta distribution.	number	Required
Alpha	A parameter of the distribution.	number	Required
Beta	A parameter of the distribution.	number	Required
A	A lower bound to the interval of x.	number	Optional
B	An upper bound to the interval of x.	number	Optional

Remarks :

• If any argument is nonnumeric, BETA.INV returns the #VALUE! error value.
• If alpha ≤ 0 or beta ≤ 0, BETA.INV returns the #NUM! error value.
• If probability ≤ 0 or probability > 1, BETA.INV returns the #NUM! error value.
• If you omit values for A and B, BETA.INV uses the standard cumulative beta distribution, so that A = 0 and B = 1.

Given a value for probability, BETA.INV seeks that value x such that BETA.DIST(x, alpha, beta, TRUE, A, B) = probability. Thus, precision of BETA.INV depends on precision of BETA.DIST.

Example : Excel BETA.INV() function
The following worksheet shows the inverse of the cumulative beta probability density function for the parameters present in sample data column in the table.

Sample Data	Description
0.69638061	Probability associated with the beta distribution
7	Parameter of the distribution
9	Parameter of the distribution
2	Lower bound
4	Upper bound

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