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GAMMADIST

The GAMMADIST function calculates the gamma distribution for a given set of parameters. The gamma distribution is a continuous probability distribution that is often used in statistics. It is commonly used to model the time between events. The function returns the probability density function or the cumulative distribution function for a given set of parameters.

Usage

Use the GAMMADIST formula with the syntax shown below, it has 4 required parameters:

=GAMMADIST(x, alpha, beta, cumulative)
Parameters:
  1. x (required):
    The value at which to evaluate the distribution.
  2. alpha (required):
    The shape parameter of the distribution.
  3. beta (required):
    The scale parameter of the distribution.
  4. cumulative (required):
    A boolean value that determines the form of the function. If TRUE, GAMMADIST returns the cumulative distribution function; if FALSE, it returns the probability density function.

Examples

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

Calculating probability density

The GAMMADIST function can be used to calculate the probability density of a gamma distribution for a given set of parameters.

Calculating cumulative distribution

The GAMMADIST function can be used to calculate the cumulative distribution of a gamma distribution for a given set of parameters.

Modeling waiting times

The gamma distribution is commonly used to model waiting times. The GAMMADIST function can be used to calculate the probability density or cumulative distribution of waiting times for a given set of parameters.

Common Mistakes

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

Missing or wrong arguments

One of the most common mistakes is not providing the correct number of arguments, or providing arguments in the wrong order. Make sure to check the syntax and provide values for x, alpha, beta, and cumulative in the correct order.

Incorrect range for arguments

Another common mistake is providing arguments that are outside the expected range. For example, x and beta must be greater than 0, and alpha and beta must not be negative. Check your input values and make sure they are within the expected range.

Incorrect interpretation of cumulative parameter

The cumulative parameter in the GAMMADIST formula determines whether to calculate the probability density function (false) or the cumulative distribution function (true). One common mistake is to misinterpret the cumulative parameter and provide the wrong value. Make sure you understand the difference between the two and provide the correct value for cumulative.

Related Formulas

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

  • GAMMAINV

    The GAMMAINV formula returns the inverse of the gamma cumulative distribution function for a given probability. This function is most commonly used for statistical analysis, particularly in modeling and simulation applications.

  • 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.

  • GAMMALN.PRECISE

    The GAMMALN.PRECISE function calculates the natural logarithm of the absolute value of the gamma function for a given positive number. The gamma function is a commonly used function in mathematics and statistics. The natural logarithm of the gamma function is useful in various fields, such as physics, biology, and engineering, for modeling various phenomena.

  • GAMMA.DIST

    The GAMMA.DIST function calculates the gamma distribution probability for a specified x value, alpha and beta parameters. This function is often used in statistics to model continuous data that is skewed to the right. It can be used to analyze data in various fields such as finance, engineering, and social sciences.

  • GAMMA.INV

    The GAMMA.INV formula returns the inverse of the cumulative distribution function for a specified probability and the Gamma distribution. It is commonly used in statistical analysis to find the value at which a specified percentage of the distribution lies. The Gamma distribution is a continuous probability distribution that is used to model the time until a certain number of events occur.

Learn More

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