[R] Error Bars ggplot2

[ONKELINX, Thierry]

How about this?

Andpleasemakeusofthelargekeyatthebottomofyourkeyboard.Itmakescodemuchmorereadable.

library(ggplot2)
spd <- factor(c("s","f","f","s","f","s","s","s","f","f","s","f"))
r <- c(4.9,3.2,2.1,.2,3.8,6.4,7.5,1.7,3.4,4.1,2.2,5)
dataset <- data.frame(spd, r)
dataset <- rbind(cbind(dataset, Type = "DOE", delta = 2),
cbind(dataset, Type = "Non-DOE", delta = 3))
ggplot(dataset, aes(x = spd:factor(r), y = r, ymin = r - delta, ymax = r + delta, colour = spd, linetype = Type)) + geom_errorbar() + geom_point()


ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
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1070 Anderlecht
Belgium
+ 32 2 525 02 51
+ 32 54 43 61 85
Thierry.Onkelinx op inbo.be
www.inbo.be

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~ Sir Ronald Aylmer Fisher

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-----Oorspronkelijk bericht-----
Van: r-help-bounces op r-project.org [mailto:r-help-bounces op r-project.org] Namens Adam Gabbert
Verzonden: donderdag 26 juli 2012 19:50
Aan: r-help op r-project.org
Onderwerp: Re: [R] Error Bars ggplot2

Hi Dennis,

Part of my problem could be that I'm unsure how to nest another variable withn spd.f.  Perhaps if I give a better explanation of my goal things will make more sense.

My intent is to calculate two sets of confidence intervals to show the benefits of a DOE approach versus a Non-DOE approach.  For example, I want to calculate the confidence intervals for "f" and "s" in two ways.  First using a DOE approach, by taking the mean of the "f" or "s" values plus/minus t-value at a 95%ci with 10df multiplied by the standard error
[mean(f-values) +- tval(.95ci,10df)*std.err].  Second using a "bin"
specific approach which only looks at the 6 "f" or "s" values (i.e,
mean(f-values) +- tval(.95ci, 5df)*std.err.mean).

This will leave me with two confidence intervals, that I want to plot side by side to show that the DOE approach confidence interval will be smaller for most cases.  I have attached a sample plot that shows the plot layout I'm trying to get.

Thanks

AG



Hi:

Your code makes no sense because the variable by which you want to dodge is the same as the one you're using on the x-axis. Dodging by subgroups is an application of visualizing nested data, which you don't have (at least in the state that you posted). For your data, this would work:

ggplot(data, aes(x = spd, y = r, colour = spd)) +
   geom_errorbar(aes(ymin = 3, ymax = 5), width = 0.1) +
   geom_point()

I don't understand the point of the second geom_errorbar() call, so I'm just avoiding it.

In order to dodge (appose groups in factor B side by side within each level of factor A), you need a third variable whose values are nested within levels of spd.f.

HTH,
Dennis

On Thu, Jul 26, 2012 at 6:03 AM, Adam Gabbert <adamjgabbert op gmail.com>
wrote:
> Hello,
>
> I'm attempting to plot error bars side by side rather than stacked on
> top of each other with ggplot2.  Here is the sample code I am using:
>
> #Code
>
> #Data
> spd<-c("s","f","f","s","f","s","s","s","f","f","s","f")
> r<-c(4.9,3.2,2.1,.2,3.8,6.4,7.5,1.7,3.4,4.1,2.2,5)
>
> #Turn spd into a factor
> spd.f<-factor(spd)
>
> #Place data into a data frame
> data<-data.frame(cbind(spd.f,r))
>
> #Load ggplot2
> library(ggplot2)
>
> #Create plot
> pd<-position_dodge(.2)
> myplot<-ggplot(data,aes(x=spd,y=r,colour=spd))+
>   geom_errorbar(aes(ymin=3,ymax=5),width=.1)+
>   geom_point()+
>
> geom_errorbar(aes(ymin=1,ymax=6),width=.1,colour="black",position=pd)
> #Display plot
> myplot
>
> I have attached a plot that my sample code produces.  As you can see
> the error bars are stacked.  How can I get them to plot side by side?
>
> Thanks
>
> AG
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