[R] Bar Plots: Error Bars

[bshan101]

Thanks so much! And those links are really useful :)

brett


Jeremy Baxter wrote:
> 
> Brett
> 
> Hi
> 
> Searching http://www.Rseek.org will return many similar results. You might
> find 
> the following useful in terms of your question re aligning the bars:
> 
> http://users.fmg.uva.nl/rgrasman/rpages/2005/09/error-bars-in-plots.html
> 
> The discussion on this page also refers to the errbar function in the
> Hmisc 
> package. There are other options, searching Rseek will provide many!
> 
> Basically something along the lines of the following will 'fix' your
> graph:
> 
> marks <- sample(4:10, size=50, replace=TRUE)
> dim(marks) <- c(10,5)                       
> classavg <- colMeans (marks, na.rm=FALSE, dims = 1)
> 
> thegraph <- barplot(classavg, main="Class Average for Quizzes",
> xlab="Quiz", 
> ylab="Average", names = c("1","2","3","4","5"), ylim=c(0,12), axis.lty=1)
> str(thegraph)
> max <- apply (marks, 2, max)                                            
> min <- apply (marks, 2, min)                                             
> arrows(thegraph, min, thegraph, max, code=3, angle=90, length=0.125)          
> 
> HTH,
> Jeremy
> 
>> Hey Everyone,
>>
>> I'm pretty new at R and wanted to try and make some graphs with dummy
>> data
>> before using it to analyze my own. I successfully made a bar graph and
>> error bars, but I can't figure out how to align them properly (currently
>> they are not centered on the bars and some of them aren't even close).
>> Here's the
>>
>> code that I'm using:
>> > marks <- sample(4:10, size=50, replace=TRUE)
>> > dim(marks) <- c(10,5)
>> > classavg <- colMeans (marks, na.rm=FALSE, dims = 1)
>> > barplot(classavg, main="Class Average for Quizzes", xlab="Quiz",
>> > ylab="Average", names = c("1","2","3","4","5"), ylim=c(0,12),
>> axis.lty=1)
>>
>> box()
>>
>> > max <- apply (marks, 2, max)
>> > min <- apply (marks, 2, min)
>> > arrows(1:5, min, 1:5, max, code=3, angle=90, length=0.125)
>>
>> The error bars are simply ranges for now (I wanted to do that before I
>> tried standard deviation/error). If anyone could help me align them it
>> would be much appreciated!
>>
>> brett
> ---------------
> Jeremy Baxter, Statistics Department, Rhodes University, South Africa.
> Views expressed above, no matter how badly spelt, are my own... I think?
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.
> 
> 

-- 
View this message in context: http://n4.nabble.com/Bar-Plots-Error-Bars-tp947407p947484.html
Sent from the R help mailing list archive at Nabble.com.