Date: Wed, 14 Jun 2006 10:35:10 -0700
Reply-To: David L Cassell <davidlcassell@MSN.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: David L Cassell <davidlcassell@MSN.COM>
Subject: Re: Construct Q-Q Plots prespecified Quantiles
Content-Type: text/plain; format=flowed
>Does anyone know how to generate Q-Q plots with your specification of
>different quantiles you're interested in looking at? I would greatly
>appreciate sample code if you have any.
Take a look at the QQPLOT statement in PROC UNIVARIATE. That gives
you the choice of normal, lognormal, 2- or 3- parameter Weibull, gamma,
exponential, and beta distributions for your quantiles.
Or you can use PROC CAPABILITY in the SAS/QC module, if you have that.
It has a QQPLOT statement too.
If you want to build your own, you will need to come up with a closed-form
expression for the inverse of the cumulative distribution function, or else
use an approximation to it. Then use Blom's adjustment to get the values.
David L. Cassell
3115 NW Norwood Pl.
Corvallis OR 97330
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