# GAMMA

The GAMMA function returns the Gamma function evaluated at the input value. The Gamma function is a commonly used function in mathematics, and is used in many statistical calculations. It is defined as the integral of t^(x-1)*e^(-t) from 0 to infinity. The GAMMA function can be used to calculate probabilities of certain events in statistical distributions.

## Usage

Use the `GAMMA` formula with the syntax shown below, it has 1 required parameter:

Parameters:
1. number (required):
The input value to evaluate the Gamma function at. Must be a positive number.

## Examples

Here are a few example use cases that explain how to use the `GAMMA` formula in Google Sheets.

### Calculate factorials of non-integer values

The Gamma function can be used to calculate factorials of non-integer values. For example, GAMMA(4.5) returns the value of 3.32335097045, which is equivalent to 4.5 factorial.

### Calculate probabilities in statistical distributions

The Gamma function is used in many statistical distributions, such as the Gamma distribution and the Chi-squared distribution. The GAMMA function can be used to calculate probabilities of certain events in these distributions.

## Common Mistakes

`GAMMA` not working? Here are some common mistakes people make when using the `GAMMA` Google Sheets Formula:

### Incorrect argument type

One common mistake is to provide an argument that is not a number or a reference to a cell containing a number. Double-check that the argument you are providing is a valid number.

### Invalid argument value

Another mistake is to provide an argument that is negative or zero. The GAMMA function requires a positive argument. Make sure the value you are providing is positive.

### Incorrect number of arguments

A common mistake is to provide more than one argument to the GAMMA function. The GAMMA function only accepts one argument. Remove any extra arguments.

### Incorrect function name

Another mistake is to misspell the function name as 'GAMMA'. Double-check that you are using the correct name 'GAMMADIST'.

### Incorrect argument order

One mistake is to provide the argument in the wrong order. The GAMMA function only accepts one argument, so make sure that the argument is provided in the correct order.

The following functions are similar to `GAMMA` or are often used with it in a formula:

• `GAMMALN`

The `GAMMALN` function returns the natural logarithm of the absolute value of the Gamma function, Γ(x). The Gamma function is defined as an extension of the factorial function to complex and real numbers. The function is commonly used in probability theory and statistics to compute probabilities and to model continuous distributions such as the chi-squared and F distributions.

• `CHISQ.DIST`

The `CHISQ.DIST` function calculates the probability density function or the cumulative distribution function of a chi-squared distribution. This function is commonly used in hypothesis testing to determine the significance of the difference between expected and observed values. The output of this function can be used to make decisions about the null hypothesis.

• `CHISQ.INV`

The CHISQ.INV function returns the inverse of the right-tailed probability of the chi-squared distribution. It is commonly used in hypothesis testing where the null hypothesis is that the observed data follows a chi-squared distribution. The function returns the value of the chi-squared random variable at which the cumulative distribution function equals the given probability. This function is useful for finding critical values after performing a chi-squared test.

• `EXPON.DIST`

The EXPON.DIST function returns the exponential distribution of a specified random variable, x, given a specified lambda, LAMBDA. The exponential distribution is commonly used to model the time between events in a Poisson process. The function returns the probability density function or the cumulative distribution function of the exponential distribution depending on whether the cumulative argument is set to TRUE or FALSE. This function is useful for analyzing reliability data and can be used to determine the probability that a component will fail before a certain time.

You can learn more about the `GAMMA` Google Sheets function on Google Support.