R help - Sep 2011 - sd help

Hello,
I am getting a strange error while computing standard deviation. If
the do the following I get the answer NA NA. Any help??? Thank you so
much.

a<- cbind()
a<- cbind(a, 5)
a<- cbind(a, 7)
print(sd(a))

If I compute the mean it works fine though i.e., print(mean(a)) works
just fine.

Hi,

You are not getting an error.  You are getting the standard deviation
of the columns as clearly described in the documentation.

Cheers,

Josh

On Sat, Sep 3, 2011 at 5:00 PM, novis <kaushik.sinha.cs at gmail.com>
wrote:
> Hello,
> I am getting a strange error while computing standard deviation. If
> the do the following I get the answer NA NA. Any help??? Thank you so
> much.
>
> a<- cbind()
> a<- cbind(a, 5)
> a<- cbind(a, 7)
> print(sd(a))
>
> If I compute the mean it works fine though i.e., print(mean(a)) works
> just fine.
>
> ______________________________________________
> 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.
>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
Programmer Analyst II, ATS Statistical Consulting Group
University of California, Los Angeles
https://joshuawiley.com/

The sd function is doing *exactly* what it should.

the sd of 5 is "NA", and the sd of 7 is "NA"

try looking at "a" itself. My guess is that you didn't intend to
have
two columns each with one value.

Did you instead intend to have 5 and 7 in one vector, like so:

a<-c(5,7)
sd(a)

Glen