[R] working with summarized data
Anupam Tyagi
AnupTyagi at yahoo.com
Fri Sep 29 10:06:07 CEST 2006
Hi Rick,
I came across your posting that I had replied to. I had assumed from
your posting that you had positive integer weights, and that you had a
certain kind of stratified sampling. For a general case, you may want to
look at "survey" package. Graphical representation of survey data,
specially large surveys, is a good research issue in statistical
graphics. R seems to be is suitable for doing this kind of work.
Anupam.
Anupam Tyagi wrote the following on 8/31/2006 10:40 AM:
> One solution is to simulate the population by repeating each row
> "weight" number of times. This is inefficient. It may create a very
> large dataset for a large sample survey. But some of graphs and other
> things may turn out to your liking, depending upon how the functions are
> written.
>
> Anupam.
>
> Rick Bischoff wrote the following on 8/30/2006 7:57 PM:
>> The data sets I am working with all have a weight variable--e.g.,
>> each row doesn't mean 1 observation.
>>
>> With that in mind, nearly all of the graphs and summary statistics
>> are incorrect for my data, because they don't take into account the
>> weight.
>>
>> ****
>> For example "median" is incorrect, as the quantiles aren't calculated
>> with weights:
>>
>> sum( weights[X < median(X)] ) / sum(weights)
>>
>> This should be 0.5... of course it's not.
>> ****
>>
>> Unfortunately, it seems that most(all?) of R's graphics and summary
>> statistic functions don't take a weight or frequency argument.
>> (Fortunately the models do...)
>>
>> Am I completely missing how to do this? One way would be to
>> replicate each row proportional to the weight (e.g. if the weight was
>> 4, we would 3 additional copies) but this will get prohibitive pretty
>> quickly as the dataset grows.
>>
>>
>> Thanks in advance!
>>
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>
>
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