Date:  Wed, 28 Jun 2000 22:29:00 0400 
ReplyTo:  Muyiwa Oladosu <oladosu@EXCELONLINE.COM> 
Sender:  "SPSSX(r) Discussion" <SPSSXL@LISTSERV.UGA.EDU> 
From:  Muyiwa Oladosu <oladosu@EXCELONLINE.COM> 
Subject:  Re: Weight Determination (fwd) 

ContentType:  text/plain; charset="iso88591" 
Thanks to everyone who spared some time to enlighten me on weighting issues.
This list serve is undoubtedly a rich reservoir of knowledge. I now have
enough info to assist me with weighting. Thanks once more.
Muyiwa.

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Original Message
From: Tim Dunsworth <Tim.Dunsworth@METROSTATE.EDU>
Newsgroups: bit.listserv.spssxl
To: SPSSXL@LISTSERV.UGA.EDU <SPSSXL@LISTSERV.UGA.EDU>
Date: Wednesday, June 28, 2000 10:54 AM
Subject: Re: Weight Determination (fwd)
>Yes, you're right Curt  it was a geezer lapse on my part that I didn't
catch because my incorrectly computed weights still managed to preserve the
total sample size (125 + 375 = 500, while the correct numbers are 100 + 400
= 500). Thanks for catching the error.
>
>>>> curtyboy@worldspy.net 06/27 6:39 PM >>>
>see below
>
>>
>> There are several types of weights in common use. Hector's reply uses one
>definition that has the advantage that all statistics (eg. cumulative
number
>of cases up to some observed value of a numeric variable) are direct
>estimates of the corresponding population values, but it has the
>disadvantage of increasing the apparent sample size and thus affecting
>significance values.
>>
>> If you want to preserve the same total sample size, calculate the weights
>as the population proportion of each group divided by the sample proportion
>of that same group. For urban dwellers that would be:
>> W = (1000/4000) / (250/500) = 0.5
>
>Tim:
>
>I'm trying to understand your recommendation. How do you define population
>proportion? In this case, I would think that population proportion =
>(1,000/5,000), and therefore the weight for urban dwellers would be:
>(1000/5000)/ (250/500) = .4.
>
>And the weight for rural dwellers would be (4,000/5,000)/(250/500) = 1.6.
>
>Am I on or off target?
>
>Curt Dommeyer
