Creating Weibull Q-Q Plots
/****************************************************************/
/* S A S S A M P L E L I B R A R Y */
/* */
/* NAME: CAPQQ3 */
/* TITLE: Creating Weibull Q-Q Plots */
/* PRODUCT: QC */
/* SYSTEM: ALL */
/* KEYS: Capability Analysis, Quantile-Quantile Plots, */
/* PROCS: CAPABILITY */
/* DATA: */
/* */
/* SUPPORT: saswgr */
/* REF: SAS/QC Software: Usage and Reference, Version 6, */
/* First Edition, Volume 1 and Volume 2 */
/* MISC: */
/* */
/* Examples in the documentation were created using the */
/* statement: ods listing style=statistical; */
/* */
/****************************************************************/
data Failures;
input Time @@;
label Time='Time in Months';
datalines;
29.42 32.14 30.58 27.50 26.08 29.06 25.10 31.34
29.14 33.96 30.64 27.32 29.86 26.28 29.68 33.76
29.32 30.82 27.26 27.92 30.92 24.64 32.90 35.46
30.28 28.36 25.86 31.36 25.26 36.32 28.58 28.88
26.72 27.42 29.02 27.54 31.60 33.46 26.78 27.82
29.18 27.94 27.66 26.42 31.00 26.64 31.44 32.52
;
title 'Three-Parameter Weibull Q-Q Plot for Failure Times';
proc capability data=Failures noprint;
qqplot Time / weibull(c=est theta=est sigma=est)
square
href=0.5 1 1.5 2
vref=25 27.5 30 32.5 35
odstitle=title;
run;
title 'Two-Parameter Weibull Q-Q Plot for Failure Times';
proc capability data=Failures noprint;
qqplot Time / weibull2(theta=24 c=est sigma=est) square
href= -4 to 1
vref= 0 to 2.5 by 0.5
odstitle=title;
run;