On Thu, Nov 8, 2012 at 12:14 PM, Rui Barradas <ruipbarradas@sapo.pt> wrote:

> Hello,
>
> If I understand it right, you can use the arrows() function with an angle
> of 90 to get ci bars.
> Using your data example, but with made up standard errors,
>
>
> a=c(10,15)
> b=c(20,24)
> c=c(21,23)
>
> hei=cbind(a,b,c)
>
> # Standard errors
> sigma <- matrix(runif(6), ncol = 3)
> # helper function
> ci <- function(x, conf = 0.95) x*qnorm(1 - (1 - conf)/2)
>
> lo <- hei - ci(sigma)
> hi <- hei + ci(sigma)
>
> graph1=barplot(hei, beside=T, ylim = c(0, max(hi)))
>

 arrows(graph1, hi, graph1, lo, length = 0.15, angle = 90, code=3)

will suffice  (code = 1,2,3 in ?arrows)



> sapply(1:ncol(graph1), function(j){
>     arrows(graph1[,j], hei[,j], graph1[,j], lo[,j], length = 0.15, angle =
> 90)
>     arrows(graph1[,j], hei[,j], graph1[,j], hi[,j], length = 0.15, angle =
> 90)
> })
>
>
> Hope this helps,
>
> Rui Barradas
> Em 08-11-2012 13:02, Thais Rangel escreveu:
>
>  Hello everyone!
>>
>> I need to include the confidence interval bar in a grouped barplot. I've
>> found some options on the web, but none of them solved my problem.
>>
>> The question is: my barplot was created using vectors for each pair of bar
>> and them combining them using cbind.
>> I mean:
>>
>> a=c(10,15)
>> b=c(20,24)
>> c=c(21,23) ...
>>
>> hei=cbind(a,b,c)
>> graph1=barplot(hei, beside=T,...)
>>
>> I've tried to include each CI in a vector just like the height of the
>> bars,
>> but it hasn't worked (!!)
>> Is there an easy way to do this??
>>
>> Thanks a lot =)
>>
>>
>> Thais Rangel
>> (Rio de Janeiro, Brazil)
>>
>>         [[alternative HTML version deleted]]
>>
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>>
>
> ______________________________**________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
> PLEASE do read the posting guide http://www.R-project.org/**
> posting-guide.html <http://www.R-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>

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