# 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.