[R] bargraph.ci - CI and color question.

[Manuel Morales]

On Tue, 2009-11-03 at 10:20 -0600, Michael Just wrote:
> Hello,
> 
> Thanks for the responses.  Yes, I did try to use ?bargraph.CI for the
> colors. When I said bars,  I meant the main bars on the graph not the
> error bars. However, this "col=c("color", "color")" is what I was
> needed and while it didn't find in the ?bargraph.ci help, I suspect
> its a  more fundamental R thing that I was unaware of.  Regardless,
> thank you for the example.
> 
> bargraph.CI(dose, len, group = supp, data =ToothGrowth,
> + col=c("gray","black"))
> 
> Regarding the confidence intervals.  Yes, I am looking for the 95%
> confidence interval of the mean.  Using the ci.fun can I get +/- 1.96
> SD?
> 
> bargraph.CI(x.factor = dose, response = len, data = ToothGrowth,
> ci.fun= function(x) c(mean(x)-sd(x), mean(x) + sd(x)) )
> 
> I tried variations on this like,
> 
> ci.fun= function(x) c(mean(x)-(1.96*sd(x))), mean(x) + (1.96*sd(x))) )

You do +/- 1.96*se to get the approximate 95% CI of the mean. +/-
1.96*SD gives the 95% CI of the distribution.

bargraph.CI(x.factor = dose, response = len, data = ToothGrowth, ci.fun=
function(x) c(mean(x)-1.96*se(x), mean(x)+1.96*se(x)) )
> 
> but this didn't work.  Maybe this approach above seems silly, but I
> hope I am exhibiting that I do indeed what the 95% CI for the mean,
> but that I am unsure how to have the error bars reflect this using the
> ci.fun argument.  Can I use this argument or is some pre-processing
> necessary?  If this information is located somewhere besides the
> ?bargraph.ci help I would greatly appreciate an indication of where it
> is.
> 
> Thank you kindly,
> Michael Just
> 
> On Tue, Nov 3, 2009 at 8:53 AM, Manuel Morales
> <Manuel.A.Morales at williams.edu> wrote:
> > On Tue, 2009-11-03 at 03:51 -0600, Michael Just wrote:
> >> Hello,
> >> When using bargraph.CI in package sciplot can the bars for each group
> >> be different colors?  How do I select the color for each group?
> >
> > With the option err.col
> >
> > bargraph.CI(dose, len, group = supp, data =ToothGrowth,
> > err.col=c("gray","black"))
> >
> >> When I use this instead of the default (SD vs SE):
> >>
> >> bargraph.CI(x.factor = dose, response = len, data = ToothGrowth,
> >>
> >>                ci.fun= function(x) c(mean(x)-sd(x), mean(x) + sd(x)) )
> >>
> >>
> >> Am I getting 95% CI bars?
> >
> > No. You're plotting +/- 1 SD.
> >>
> >> Thank you kindly,
> >> Michael Just
> >>
> >> ______________________________________________
> >> 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.
> >
> >
> > --
> > http://mutualism.williams.edu
> >
> >


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