Returns the inverse of the cumulative beta probability distribution function. That is, if probability = BETADIST(x,...), then BETAINV(probability,...) = x. The cumulative beta distribution can be used in project planning to model probable completion times given an expected completion time and variability.
Syntax
BETAINV(probability,alpha,beta,A,B)
Probability is a probability associated with the beta distribution.
Alpha is a parameter to the distribution.
Beta is a parameter to the distribution.
A is an optional lower bound to the interval of x.
B is an optional upper bound to the interval of x.
Remarks
- If any argument is nonnumeric, BETAINV returns the #VALUE! error value.
- If alpha ≤ 0 or beta ≤ 0, BETAINV returns the #NUM! error value.
- If probability ≤ 0 or probability > 1, BETAINV returns the #NUM! error value.
- If you omit values for A and B, BETAINV uses the standard cumulative beta distribution, so that A = 0 and B = 1.
BETAINV uses an iterative technique for calculating the function. Given a probability value, BETAINV iterates until the result is accurate to within ±3x10^-7. If BETAINV does not converge after 100 iterations, the function returns the #N/A error value.
Example
| Probability | Alpha | Beta | A | B | Formula | Description (Result) |
|---|---|---|---|---|---|---|
| 0.685470581 | 8 | 10 | 1 | 3 | =BETAINV([Probability],[Alpha],[Beta],[A],[B]) | Inverse of the cumulative beta probability density function for the parameters (2) |