# WorksheetFunction.Beta_Inv (Excel)

Returns the inverse of the cumulative distribution function for a specified beta distribution. That is, if probability = Beta_Dist(x,...), then Beta_Inv(probability,...

The beta distribution can be used in project planning to model probable completion times given an expected completion time and variability. If any argument is nonnumeric, Beta_Inv generates an error value. If alpha ≤ 0 or beta ≤ 0, Beta_Inv generates an error value. If probability ≤ 0 or probability > 1, Beta_Inv generates an error value. If you omit values for A and B (lower and upper bound), 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, the precision of Beta_Inv depends on the precision of Beta_Dist. Beta_Inv uses an iterative search technique.

Beta_Inv (Arg1, Arg2, ..., Arg5)

``````
Dim dblArg1 As Double: dblArg1 =
Dim dblArg2 As Double: dblArg2 =
Dim dblArg3 As Double: dblArg3 =
Dim dblBeta_Inv As Double
dblBeta_Inv = WorksheetFunction.Beta_Inv(Arg1:=dblArg1, Arg2:=dblArg2, Arg3:=dblArg3)
``````

## Arguments

Arg1, Arg2, ..., Arg5

Arg1 (Double) - A probability associated with the beta distribution.

Arg2 (Double) - The Alpha parameter of the distribution.

Arg3 (Double) - The Beta parameter the distribution.

Arg4 - An optional lower bound to the interval of x

Arg5 - An optional upper bound to the interval of x