Hi I'm new to R and most things I want to do I can do but I'm stuck on how to weight a sample. I have had a look through the post but I can't find anything that addresses my specific problem. I am wanting to scale up a sample which has been taken based on a single variable (perf) which has 4 attributes H,I, J and K. The make up of the sample is shown below:- Perf Factored Count (A) Raw Count (B) Factor (A/B) H 5,945 2,924 2.033174 I 1,305 2,436 0.535714 J 2,000 2,092 0.956023 K 750 1,225 0.612245 I then want to produce all further analysis based on this factored sample. I can produce a weighted sample in SAS using the weight function which I have shown below wt=0; if perf='H' then wt=2.033174; if perf='I ' then wt=0.535714; if perf='J ' then wt=0.956023; if perf='K ' then wt=0.612245; proc freq data=DD.new; tables resdstat; weight wt; run; Does anyone know how to reproduce this in R? Thanks very much -- View this message in context: http://r.789695.n4.nabble.com/Creating-a-weighted-sample-Help-tp3331842p3331842.html Sent from the R help mailing list archive at Nabble.com.
LouiseS wrote:> Hi > > I'm new to R and most things I want to do I can do but I'm stuck on how to > weight a sample. I have had a look through the post but I can't find > anything that addresses my specific problem. I am wanting to scale up a > sample which has been taken based on a single variable (perf) which has 4 > attributes H,I, J and K. The make up of the sample is shown below:- > > Perf Factored Count (A) Raw Count (B) Factor (A/B) > H 5,945 2,924 2.033174 > I 1,305 2,436 0.535714 > J 2,000 2,092 0.956023 > K 750 1,225 0.612245 > > > I then want to produce all further analysis based on this factored sample. > I can produce a weighted sample in SAS using the weight function which I > have shown below > > wt=0; > if perf='H' then wt=2.033174; > if perf='I ' then wt=0.535714; > if perf='J ' then wt=0.956023; > if perf='K ' then wt=0.612245; > > proc freq data=DD.new; > tables resdstat; > weight wt; > run; > > Does anyone know how to reproduce this in R?I don't know what you mean by "all further analysis", but if you want weighted mean, variance, quantile, have a look at ?wtd.mean in the Hmisc package. Just use your A/B values in a weights vector. Peter Ehlers> > Thanks very much > > -- > View this message in context: http://r.789695.n4.nabble.com/Creating-a-weighted-sample-Help-tp3331842p3331842.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- > project.org] On Behalf Of LouiseS > Sent: Thursday, March 03, 2011 5:21 AM > To: r-help at r-project.org > Subject: Re: [R] Creating a weighted sample - Help > > Hi > > Thanks for responses. The sample I have taken is a random sample from > H, I, > J and K. The further analysis I want to do is all around bad debt > rates so > it could be (H/H+I)*100 = Bad rate percentage also population stability > calculations that are all related to credit scoring. I want to be able > to > report back on any variable that I have in my data set based on my > factored > counts (A) of 10,000 - so every calculation is based on 10,000 account > in > the correct proportions. > > Does his help? > > Thanks once again > Louise >Louise, It appears that you have done a stratified random sample of four types of accounts and have oversampled the less frequent account types. You definitely should consider doing your analyses using the survey package (or similar package) that appropriately accounts for the sampling variability. Otherwise, your variances / standard errors are going to be incorrect. Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204