 Dataplot Vol 2 Auxiliary Chapter

# WEIHAZ

Name:
WEIHAZ (LET)
Type:
Library Function
Purpose:
Compute the Weibull hazard function with tail length parameter .
Description:
For the minimum order statistic, the standard form of the Weibull hazard function is: For the maximum order statistic, the standard form of the Weibull hazard function is: Syntax:
LET <y> = WEIHAZ(<x>,<gamma>,<loc>, <scale>)
<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 Weibull hazard value is stored;
<gamma> is a positive number, parameter, or variable that specifies the tail length parameter;
<loc> is a positive number, parameter, or variable that specifies the location parameter;
<scale> is a positive number, parameter, or variable that specifies the scale parameter;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

The location and scale parameters are optional.

Examples:
LET A = WEIHAZ(3,2)
LET Y = WEIHAZ(X,4)
LET Y = WEIHAZ(X,2,0,5)
PLOT WEIHAZ(X,2) FOR X = 0.01 0.01 10
Note:
The SET MINMAX command specifies whether the minimum or maximum order statistic form is used. Entering SET MINMAX 2 specifies the maximum order statistic while entering SET MINMAX specifies the minimum order statistic.
Note:
For the minimum order statistic, the general form of the Weibull hazard function is: For the maximum order statistic, the general form of the Weibull probability density function is: where is the location parameter and is the is the scale parameter.

Default:
None
Synonyms:
None
Related Commands:
 WEICHAZ = Compute the Weibull cumulative hazard function. WEICDF = Compute the Weibull cumulative distribution function. WEIPDF = Compute the Weibull probability density function. WEIPPF = Compute the Weibull percent point function. EXPHAZ = Compute the exponential cumulative hazard function. EV1HAZ = Compute the extreme value type I hazard function. EV2HAZ = Compute the extreme value type II hazard function. LGNHAZ = Compute the lognormal hazard function.
Reference:
"Continuous Univariate Distributions--Vol. I", 2nd. Ed., Johnson, Kotz, and Balakrishnan, John Wiley and Sons, 1994.

"Statistical Distributions", 2nd. Edition, Evans, Hastings, and Peacock, Wiley and Sons, 1993 (chapter 18).

Applications:
Reliability Analysis
Implementation Date:
1998/5
Program:
MULTIPLOT 2 2
MULTIPLOT CORNER COORDINATES 0 0 100 100
SET MINMAX 1
X1LABEL GAMMA = 1
PLOT WEIHAZ(X,1) FOR X = 0.01 0.01 3
X1LABEL GAMMA = 2
PLOT WEIHAZ(X,2) FOR X = 0.01 0.01 3
X1LABEL GAMMA = 5
PLOT WEIHAZ(X,5) FOR X = 0.01 0.01 3
X1LABEL GAMMA = 0.5
PLOT WEIHAZ(X,0.5) FOR X = 0.01 0.01 3
END OF MULTIPLOT
MOVE 50 97
JUSTIFICATION CENTER
TEXT WEIBULL HAZARD PLOTS

Date created: 6/5/2001
Last updated: 4/4/2003
Please email comments on this WWW page to alan.heckert@nist.gov.