error bars on barplot

On 04/09/2010 08:55 PM, Samantha Reynolds wrote:

Hi

I was hoping someone might be able to help me I have this data:

birdid timetaken numvisits ptachchoice time bold
    1087         8        10           1   AM    0
    1087        28         6           1   PM    0
    1087        13         3           2   AM    0
    1087       121         0           2   PM    0
    1046       121         0           1   AM    1
    1046       121         0           1   PM    1

i've plotted the means like this:

by(numvisits,patchchoice,summary)
numvisits.means<-
by(numvisits,list(time=time,patchchoice=patchchoice),mean)
numvisits.means
barplot(numvisits.means,xlab="Patch Choice",ylab="Number of
Visits",col=c("red","darkblue"),beside=T,ylim=c(0,4))
labs<-c("AM","PM")
legend(1.09,3.98,labs,fill=cols)

and need to add error bars, but i'm unsure as to how to do this.

Hi Sam,
Perhaps I should submit a FAQ on this one. Try:

bar.err (agricolae)
plotCI (gplots)
xYplot (Hmisc)
error.bars (psych)
dispersion (plotrix)
plotCI (plotrix)

and there are probably others.

Jim