# [R] Odp: NA's in survey analysis

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

```Hi

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)
x
[1] 1    1    3    3    3    2    3    <NA> 3    1    2    <NA> 3    <NA>
2
[16] 2    3    1    <NA> 3
Levels: 1 2 3 <NA>
> y<-rnorm(20)
boxplot(split(y,x))

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

Regards
Petr

> 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
> WAY TO DO STUFF IN R :)
>
> 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
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help