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
In-Reply-To:  <200606141512.k5EAkQtq006927@malibu.cc.uga.edu>
Content-Type: text/plain; format=flowed

stats112@GMAIL.COM wrote:
>Dear All,
>
>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.
>
>Thanks!

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.

HTH,
David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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