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Dataplot Vol 2 Vol 1

EWECHAZ

Name:
    EWECHAZ (LET)
Type:
    Library Function
Purpose:
    Compute the standard form of the exponentiated Weibull cumulative hazard function with shape parameters gamma and theta.
Description:
    The standard form of the exponentiated Weibull cumulative hazard function is:

      H(x,gamma,theta) = -DLOG[1-(1-EXP[-(x)**gamma])**theta]
        0 < x < infinity, gamma, theta > 0

    where gamma and theta are shape parameters.

Syntax:
    LET <y> = EWECHAZ(<x>,<gamma>,<theta>)             <SUBSET/EXCEPT/FOR qualification>
    where <x> is a variable, number, or parameter;
                  <y> is a variable or a parameter (depending on what <x> is) where the computed exponentiated Weibull cumulative hazard value is stored;
                  <gamma> is a positive number, parameter, or variable that specifies the first shape parameter;
                  <theta> is a positive number, parameter, or variable that specifies the second shape parameter;
    and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
    LET A = EWECHAZ(3,2,3)
    LET A = EWECHAZ(A1,4,0.5)
    LET X2 = EWECHAZ(X1,2,1.5)
    LET X2 = EWECHAZ(X1,GAMMA,THETA)
Note:
    The general form of the exponentiated Weibull cumulative hazard function includes the location parameter mu and the scale parameter sigma. The general form of the cumulative hazard function can be computed from the standard form of the cumulative hazard function:

      H(x,gamma,theta,mu,sigma) = H((x-mu)/sigma,gamma,theta)
Default:
    None
Synonyms:
    None
Related Commands:
    EWECDF = Compute the exponentiated Weibull cumulative distribution function.
    EWEHAZ = Compute the exponentiated Weibull hazard function.
    EWEPDF = Compute the exponentiated Weibull probability density function.
    EWEPPF = Compute the exponentiated Weibull percent point function.
    WEIPDF = Compute the Weibull probability density function.
    EXPPDF = Compute the exponential probability density function.
    GAMPDF = Compute the gamma probability density function.
    GGDPDF = Compute the generalized gamma probability density function.
    IGAPDF = Compute the inverted gamma probability density function.
    CHSPDF = Compute the chi-square probability density function.
    NORPDF = Compute the normal probability density function.
Reference:
    "The Exponentiated Weibull Family: A Reanalysis of the Bus-Motor-Failure Data", Mudholkar, Srivastava, and Friemer, Technometrics, November, 1995 (pp. 436-445).
Applications:
    Reliability Analysis
Implementation Date:
    1998/5
Program:
    LET G = DATA 1 1 1 0.5 0.5 0.5 2 2 2 
    LET C = DATA 0.5 1 2 0.5 1 2 0.5 1 2 
    LET START = DATA 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01
    LET INC = DATA 0.001 0.01 0.01 0.001 0.01 0.01 0.01 0.01 0.01 
    LET STOP = DATA 0.5 5 5 1 5 5 5 5 2
    . 
    MULTIPLOT 3 3 
    MULTIPLOT CORNER COORDINATES 0 0 100 100 
    TITLE AUTOMATIC 
    LOOP FOR K = 1 1 9 
       LET G1 = G(K) 
       LET C1 = C(K) 
       LET FIRST = START(K) 
       LET LAST = STOP(K) 
       LET INCT = INC(K) 
       X1LABEL GAMMA = ^G1, C = ^C1 
       PLOT EWECHAZ(X,^G1,^C1) FOR X = ^FIRST ^INCT ^LAST 
    END OF LOOP
    END OF MULTIPLOT
        
    plot generated by sample program

Date created: 11/13/2002
Last updated: 4/4/2003
Please email comments on this WWW page to alan.heckert@nist.gov.