Documentation/Calc Functions/GAMMA.INV

    From The Document Foundation Wiki

    Function name:

    GAMMA.INV

    Category:

    Statistical Analysis

    Summary:

    Calculates the inverse of the cumulative distribution function for a gamma distribution.

    The gamma distribution is a family of continuous probability distributions that are typically used to model positive variables that have right-skewed distributions. The distribution has two characteristic positive real numbers, usually denoted as alpha (α) and beta (β), that control its shape and rate respectively.

    GAMMA.INV uses an iterative algorithm to calculate a value [math]\displaystyle{ x }[/math] such that [math]\displaystyle{ \text{GAMMA.DIST}(x;\: α;\: β;\:1)\:=\:p }[/math], where the given probability [math]\displaystyle{ p }[/math] lies in the range [0, 1).

    Syntax:

    GAMMA.INV(Number; Alpha; Beta)

    Returns:

    Returns a non-negative real number, which is the value of the random variable that would give the specified probability in the cumulative distribution function for the specified gamma distribution.

    Arguments:

    Number is a real number in the range [0, 1), or a reference to a cell containing that number, which is a probability in the cumulative distribution function of the gamma distribution.

    Alpha is a positive real number, or a reference to a cell containing that number, which is the value of the shape parameter of the gamma distribution.

    Beta is a positive real number, or a reference to a cell containing that number, which is the value of the rate parameter of the gamma distribution.

    • If any of Number, Alpha, or Beta is non-numeric, then GAMMA.INV reports a #VALUE! error.
    • If either Alpha or Beta is less than or equal to 0.0, then GAMMA.INV reports an invalid argument error (Err:502).
    • If Number is not inside the range 0.0 <= Number < 1.0, then GAMMA.INV reports an invalid argument error (Err:502).

    Additional details:

    • Calc's GAMMAINV and GAMMA.INV functions perform the same calculations. The requirements for GAMMAINV are specified in ODF 1.2; GAMMA.INV is provided for interoperability with Microsoft Excel.
    • The name space for GAMMA.INV is COM.MICROSOFT.GAMMA.INV.
    • For more information on the gamma distribution, visit Wikipedia's Gamma distribution page.

    Examples:

    Formula Description Returns
    =GAMMA.INV(A1; A2; A3) where cells A1:A3 contain the values 0.178647117849697, 3.4 and 2.7 respectively. The function calculates an inverse value for the cumulative distribution function for a specified gamma distribution. Note that the formula =GAMMA.DIST(4.7; 3.4; 2.7; 1) returns 0.178647117849697. 4.70000000000001
    =GAMMA.INV(0; 2.3; 4.5) The function calculates the inverse value of the cumulative distribution function for the specified gamma distribution for a probability of 0. 0
    =GAMMA.INV(0.9999; 2.3; 4.5) The function calculates the inverse value of the cumulative distribution function for the specified gamma distribution for a probability close to 1.0. 55.9546104066952

    Related LibreOffice functions:

    GAMMA.DIST

    GAMMADIST

    GAMMAINV

    ODF standard:

    None

    Related (or similar) Excel functions:

    GAMMA.INV