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Dataplot Vol 2 Vol 1

LPOPPF

Name:
    LPOPPF (LET)
Type:
    Library Function
Purpose:
    Compute the Lagrange-Poisson percent point function.
Description:
    The Lagrange Poisson distribution has probability mass function

      p(x;lambda,theta) = theta*(theta+x*lambda)**(x-1)*
EXP(-theta-x*lambda)/x!    x = 0, 1, ...; 0 < ;lambda < 1; theta > 0

    with theta and lambda denoting the shape parameters.

    The cumulative distribution function is computed by summing the probability mass function. The percent point function is the inverse of the cumulative distribution function and is obtained by computing the cumulative distribution function until the specified probability is reached.

Syntax:
    LET <y> = LPOPPF(<p>,<lambda>,<theta>)>
                            <SUBSET/EXCEPT/FOR qualification>
    where <p> is a variable, number, or parameter in the interval (0,1);
                <lambda> is a number or parameter in the range (0,1) that specifies the first shape parameter;
                <theta> is a positive number or parameter that specifies the second shape parameter;
                <y> is a variable or a parameter where the computed Lagrange-Poisson ppf value is stored;
    and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
    LET A = LPOPPF(0.95,0.5,3)
    LET Y = LPOPPF(P,0.3,2)
    PLOT LPOPPF(P,0.3,2) FOR P = 0 0.01 0.99
Default:
    None
Synonyms:
    None
Related Commands:
    LPOCDF = Compute the Lagrange-Poisson cumulative distribution function.
    LPOPDF = Compute the Lagrange-Poisson probability mass function.
    BTAPDF = Compute the Borel-Tanner probability mass function.
    LOSPDF = Compute the lost games probability mass function.
    POIPDF = Compute the Poisson probability mass function.
    HERPDF = Compute the Hermite probability mass function.
    BINPDF = Compute the binomial probability mass function.
    NBPDF = Compute the negative binomial probability mass function.
    GEOPDF = Compute the geometric probability mass function.
Reference:
    Johnson, Kotz, and Kemp (1992), "Univariate Discrete Distributions", Second Edition, Wiley, pp. 394-400.

    P. C. Consul (1989), "Generalized Poisson Distributions", Dekker, New York.

Applications:
    Distributional Modeling
Implementation Date:
    2006/6
Program:
     
    title size 3
    tic label size 3
    label size 3
    legend size 3
    height 3
    multiplot scale factor 1.5
    x1label displacement 12
    y1label displacement 17
    .
    multiplot corner coordinates 0 0 100 95
    multiplot scale factor 2
    label case asis
    title case asis
    case asis
    tic offset units screen
    tic offset 3 3
    title displacement 2
    x1label Probability
    y1label X
    .
    xlimits 0 1
    major xtic mark number 6
    minor xtic mark number 3
    .
    multiplot 2 2
    .
    title Lambda = 0.3, Theta = 1
    plot lpoppf(p,0.3,1) for p = 0  0.01  0.99
    .
    title Lambda = 0.5, Theta = 1
    plot lpoppf(p,0.5,1) for p = 0  0.01  0.99
    .
    title Lambda = 0.7, Theta = 1
    plot lpoppf(p,0.7,1) for p = 0  0.01  0.99
    .
    title Lambda = 0.9, Theta = 1
    plot lpoppf(p,0.9,1) for p = 0  0.01  0.99
    .
    end of multiplot
    .
    justification center
    move 50 97
    text Percent Point for Lagrange-Poisson
        
    plot generated by sample program

Date created: 6/20/2006
Last updated: 6/20/2006
Please email comments on this WWW page to alan.heckert@nist.gov.