I am new to R.

I want to graph group data using a "Traditional Bar Chart with Standard
Error Bar", like the kind shown here:
http://samiam.colorado.edu/~mcclella/ftep/twoGroups/twoGroupGraphs.html

Is there a simple way to do this?

So far, I have only figured out how to plot the bars using barplot.

testdata <- scan(, list(group=0,xbar=0,se=0))
400 0.36038 0.02154
200 0.35927 0.02167
100 0.35925 0.02341
50 0.35712 0.01968
25 0.35396 0.01931

barplot(testdata$xbar, names.arg=as.character(testdata$group), main="a=4.0",
xlab="Group", ylab="xbar")
xvalues <- c(0.7, 1.9, 3.1, 4.3, 5.5)
arrows(xvalues, testdata$xbar, xvalues, testdata$xbar+testdata$se, length=
0.4, angle=90, code=3)


The best clue I have so far is Rtips #5.9:
http://pj.freefaculty.org/R/Rtips.html#5.9 which is what I based my present
solution off of.

However, I do not understand how this works.  It seems like there is no
concrete way to determine the arrow drawing parameters x0 and x1 for a
barplot.  Moreover, the bars seem to be "cut off".

	[[alternative HTML version deleted]]

