[R] Odp: NA's in survey analysis

Petr PIKAL petr.pikal at precheza.cz
Tue Dec 21 11:20:37 CET 2010


r-help-bounces at r-project.org napsal dne 21.12.2010 11:02:07:

> Hello,
> I am trying to analyze sociological survey data using R. It is often
> important in survey to calculate both the actual factor sums and
> percentages (easily done with describe() ), but also the numbers and
> total percentage of NA's. Often it is important to present NA's in
> graphs besides the factors.
> Is there any easy way to make R treat NA's as if those were factors
> besides other factors?
> Now, describe(data$a) gives me percentages only for the factors. So I
> have to redo percentages manually.
> barplot() also ignores NA's. So, to include NA's into barplot I need
> to do a table more or less manually.
> The other way to do it is to convert NA's into factors (doable,
> although, unlike in SPSS, I cannot make an assumption that 99 is a

not necessary to code missing values, you can set NA as one level.

x<-factor(sample(c(1:3, NA),20,replace=T), exclude=NULL)
 [1] 1    1    3    3    3    2    3    <NA> 3    1    2    <NA> 3    <NA> 
[16] 2    3    1    <NA> 3 
Levels: 1 2 3 <NA>
> y<-rnorm(20)

Besides you could find it from factor help page as I did.


> good code for a factor "NA" – it has to be the next number in the
> factor list,so, might be different for each column in a data frame).
> And besides, I have read somewhere in this list that IT IS THE WRONG
> Is there the right way to do things that I want, and if not – what are
> the possible workarounds, smarter than the ones I listed?
> --
> Donatas Glodenis
> -- 
> Donatas Glodenis
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