# [R] Plotting multiple confidence intervals in the same graph

David Carlson dcarlson at tamu.edu
Thu Nov 21 16:33:12 CET 2013

```Maybe something like this, assuming mean=0:

samsize <- 100
replicates <- 50
pval <- .05

samples <- replicate(replicates, rnorm(samsize))
confint <- t(apply(samples, 2, function(x)
c(mean(x)-qt(1-pval/2,
df=samsize-1)*sd(x)/sqrt(samsize),
mean(x)+qt(1-pval/2, df=samsize-1)*sd(x)/sqrt(samsize))))

# Simple plot
plot(c(0, 0), c(1, replicates), col="black", typ="l",
ylab="Samples",
xlab="Confidence Interval")
segments(confint[,1], 1:replicates, confint[,2], 1:replicates)

# Use red if mean outside interval
outside <- ifelse(confint[,1]>0 | confint[,2]<0, 2, 1)
plot(c(0, 0), c(1, replicates), col="black", typ="l",
ylab="Samples",
xlab="Confidence Interval")
segments(confint[,1], 1:replicates, confint[,2], 1:replicates,
col=outside)

-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352

-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of PIKAL Petr
Sent: Thursday, November 21, 2013 8:13 AM
To: Preetam Pal; r-help at r-project.org
Subject: Re: [R] Plotting multiple confidence intervals in the
same graph

Hi

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Preetam Pal
> Sent: Thursday, November 21, 2013 12:10 PM
> To: r-help at r-project.org
> Subject: [R] Plotting multiple confidence intervals in the
same graph
>
> Hi,
>
> I have 100 observations X1,X2,......,X100 and the confidence
interval
> limits for the mean at 5% level of significance.
> I wanted to repeat this procedure say 50 times and see how
many times
> the hypothetical mean is included in the confidence intervals.

Hm, I do not understand well what procedure you want to repeat
50 times?

> Analytically I have done this, but I am thinking if I can plot
the 50
> confidence interval in the same graph and may be have a
vertical line
> denoting the hypothetical mean. This will be a good visual
> representation I think.Can I use different colors as well?

If you want to have 50 colours you will not be able to
distinguish differences. How do you want to plot 50 confidence
intervals?

Something like that comes to mind but you shall be more specific

plot(1,1, type="n")
arrows(1,.8,1,1.2, angle=90, code=3)
abline(h=1.1, col=2)

Regards
Petr

>
> I request for your help on this.
>
> Thanks and Regards,
> Preetam
>
>
> --
> Preetam Pal
> (+91)-9432212774
> M-Stat 2nd Year,
Room No.
> N-114
> Statistics Division,
> C.V.Raman
> Hall
> Indian Statistical Institute,
B.H.O.S.
> Kolkata
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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http://www.R-project.org/posting-
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> and provide commented, minimal, self-contained, reproducible
code.

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