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10.08.2008 at 08:57AM PDT, ID: 23797856
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9.2

Plot means with confidence intervals by groups in R

Asked by justearth in Probability & Statistics, Math & Science, Microsoft Excel Spreadsheet Software

Hello,
I am trying to plot a graph that uses the mean instead of a density/count on the Y-axis. I of course want to use groups and I would like to also include error bars (standard deviation). I found this code below. My data is in a different format.

Q1: How can I select data that has 'scape' = 2 and 'Pri_No' = 1 or 2.
Q2: Plot this selection for one of the other variable i.e. bbED
So this plot would have the mean bbED from scape=2 and the groups to be plotted would be Pri_No = 1 & 2.

I have also considered using:
bargraph.CI  (http://mutualism.williams.edu/sciplot/)
or barp function in the plotrix package

Thanks,
justearth
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# ------- bar plot for STD, 95%CI and SEM ------
 
 
a <- c(25, 30, 34, 38, 43, 43, 46, 46, 49, 49, 52, 52, 55, 55, 58, 58, 62, 64,
66, 75)
b <- c(5, 5, 35, 44, 44, 47, 51, 55, 55, 58, 58, 62, 64, 64, 67, 67, 71, 74,
79, 85)
 
 
   ## Convert data vectors to dataframes
   adf <- data.frame(Group = " Group A ", Measure = a)
   bdf <- data.frame(Group = " Group B ", Measure = b)
 
   ## Combine into a dataframe using rbind
   abData <- rbind(adf, bdf)
 
attach(abData)
 
tmp = split(Measure, Group)
 
means = sapply(tmp, mean)
medians = sapply(tmp, median)
 
stdev = sapply(tmp, sd)
 
# to calculate SE
require(sciplot)
se = sapply(tmp, se)
 
n     <- sapply(tmp, length)
ciw   <- qt(0.975, n) * stdev / sqrt(n)
 
# to make the 3 graphs in one row...
# however they actually don't look nice :-(
# maybe by controlling the "ylim" part things get better
par(mfrow=c(1,3))
 
# typeface set to Serif (or Times)
par(family="serif")
 
# ----- bar plot with SD
require(gplots)
plotCI(barcol="blue", pch=16, col="blue", barplot(means, col=c("white",
"gray90"),
      ylim=c(0,max(means + stdev)), xlab = "Error bars: ±1SD", ylab="Measure")
       , means, stdev,
      add=TRUE)
 
# --------- bar plot with 95%CI
 
plotCI(barcol="red", pch=16, col="red", barplot(means, col=c("white", "grey90"),
      ylim=c(0,max(means + ciw)), xlab = "Error bars: 95% CI", ylab="Measure"),
means, uiw=ciw,
        add=TRUE)
Attachments:
 
justearth-data-ee.xls (1.3 MB) (File Type Details) 
Spreadsheet with values to create plots
 
[+][-]10.08.2008 at 09:49AM PDT, ID: 22670771

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[+][-]10.08.2008 at 10:20AM PDT, ID: 22671032

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[+][-]10.09.2008 at 02:04AM PDT, ID: 22676604

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About this solution

Zones: Probability & Statistics, Math & Science, Microsoft Excel Spreadsheet Software
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Solution Provided By: oheil
Participating Experts: 1
Solution Grade: A
 
 
[+][-]10.09.2008 at 02:07AM PDT, ID: 22676617

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