The frequent formulation of the beta distribution is also known as the beta distribution of the first type., while the beta distribution of the second type is an alternative name for the main beta distribution.

The **BETA.INV** The function returns the inverse of the cumulative probability density function beta (**BETA.DIST**). Be careful: there is an equivalent function called **BETAINV** which is slightly different (more next time).

And **probability** = **BETA.DIST**(**X**…**TRUE**), subsequently **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.

The **BETA.INV **The function uses the following syntax to operate:

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

The **BETA.INV** The function has the following arguments:

**probability**: required. This represents a**probability**associated with beta distribution**alfa**: additionally required. This is a parameter of the distribution**beta**: required. This is also a parameter of the distribution**A**: Optional. This is a lower limit for the interval of**X****B**: this is also optional. This is an upper limit for the interval of**X**.

It should be noted at the same time that:

- If any argument is not numeric,
**BETA.INV**return the*#VALUE!*error value - And
**alfa**≤ 0 O**beta**≤ 0,**BETA.INV**return the*#ON ONE!*error value - And
**probability**≤ 0 O**probability**> 1,**BETA.INV**return the*#ON ONE!*error value - If you omit values for
**A**Y**B**,**BETA.INV**uses the standard cumulative beta distribution, so that**A**= 0 Y**B**= 1 - This function first appeared in Excel 2010 and is not backward compatible. It is essentially a more flexible version of its predecessor,
**BETAINV**.

Given a probability value, **BETA.INV** look for that value **X** such that **BETA.DIST (x, alpha, beta, TRUE, A, B)** = probability. Therefore, the precision of **BETA.INV** depends on the precision of **BETA.DIST**.

Here is an example: