# BETA.INV

Formulas / BETA.INV
Compute the inverse of the beta cumulative probability density function.
`BETA.INV(probability, alpha, beta, [A], [B])`
• probability - the probability associated to the beta distribution
• alpha - a parameter of the distribution
• beta - a parameter of the distribution
• A - [OPTIONAL] sets a lower bound for the interval of x
• B - [OPTIONAL] an upper limit to the interval of x

## Examples

• `=BETA.INV(0.8, 2, 3, 4, 5)`

The BETA.INV function can be used to calculate the inverse cumulative beta probability density function. This is useful for determining the probability that a random variable will be less than or equal to a given value. For example, this formula will calculate the probability that a random variable is less than or equal to 0.8 given that it has a beta distribution with parameters 2, 3, 4, and 5.

• `=BETA.INV(0.5, 1, 2, 3, 4)`

The BETA.INV function can also be used to calculate the value of a random variable given its beta distribution parameters and the probability that it is less than or equal to that value. For example, this formula will calculate the value of a random variable given that it has a beta distribution with parameters 1, 2, 3, and 4 and that the probability that it is less than or equal to that value is 0.5.

• `=BETA.INV(1-0.7, 10, 20, 30, 40)`

The BETA.INV function can also be used to calculate the value of a random variable given its beta distribution parameters and the probability that it is greater than or equal to that value. For example, the above formula will calculate the value of a random variable given that it has a beta distribution with parameters 10, 20, 30, and 40 and that the probability that it is greater than or equal to that value is 0.7 .

## Summary

The BETA.INV function computes the inverse of the beta cumulative probability density function, which is used in project planning to model probable completion times.

• The BETA.INV function throws an error if any of its arguments are not numeric (#VALUE!) or if alpha or beta are less than or equal to zero (#NUM!). It also throws an error if probability is less than or equal to zero or greater than one (#NUM!).
• The beta distribution is commonly used in project planning, as it models probable completion times with an expected completion time and variability.
• The precision of the BETA.INV function is dependent on the precision of BETA.DIST.

What is the BETA.INV function?
The BETA.INV function calculates the inverse of the BETA.DIV function. BETA.DIV is the cumulative probability density function of the beta distribution. The beta distribution is commonly used to model project completion times, based on an expected completion time and the variability of the completion time.
What does the BETA.INV function accept as an argument?
The BETA.INV function accepts a probability argument.
What are the default values for the BETA.INV function?
The BETA.INV uses the standard cumulative beta distribution of A = 0 and B = 1 if A and B are omitted.
How accurate is the BETA.INV function?
The accuracy of BETA.INV is dependent on the precision of BETA.DIST. 