

Dear list
members,

I would
like to create two series of plotted mean values and error bars, yet with
different locations along the x-axis. 
Plotting of
first series using plotCI with the standard arguments goes without any problem.
However I do not succeed to add the second series in the same plot, which
should be horizontally shifted from the first series along the x-axis. The “add=TRUE”
argument works well. Is there any argument defining the series location within
plotCI. For example the tool “boxplot” contains the “at” argument. I found
examples of plotCI where a vertical shift is realized (e.g.  “x=means+1e5”), never a horizontal shift. 

Here
you find data information:

##data
value1<-c(1,2,1,2,1,3,4,2,6,1,3,4,2,6)
value2<-c(1,5,1,2,4,4,4,3,3,1,3,4,9,8)
typo<-c("C","C","C","C","A","A","A","A","A","B","B","B","B","B")
tab1<-data.frame(data=cbind(value1,value2,typo))
colnames(tab1)<-c("value1","value2","typo")
 
tab1$value1<-as.numeric(tab1$value1)
tab1$value2<-as.numeric(tab1$value2)

##mean and error first data series 

tmp <-
split(tab1$value1,tab1$typo)
means <-
sapply(tmp, mean)
stdev <-
sapply(tmp, sd)
n <-
sapply(tmp,length)
ciw <-
qt(0.975, n) * stdev / sqrt(n)

##plotting
first data series 
plotCI(x=means,uiw=stdev,
col="red", barcol="red", lwd=3, pch=18,
cex=2,
xaxt="n", yaxt="n",  ylab='benefit',xlab='typo', yaxs = 'i',ylim=c(0,8))
axis(side=1,
at=1:3, labels=names(tmp), cex=0.7)
 

##mean and error second data series 

tmp <-
split(tab1$value2,tab1$typo)
means <-
sapply(tmp, mean)
stdev <-
sapply(tmp, sd)
n <-
sapply(tmp,length)
ciw <-
qt(0.975, n) * stdev / sqrt(n)

##the
problem: plotting second dataseries 
plotCI(x=means,
uiw=stdev, col="steelblue", barcol="steelblue", lwd=2,
pch=18,
cex=2,
xaxt="n", yaxt="n", ylab='qualite',xlab='type', yaxs =
'i',add=T)  ##this series of data is now superposed,
but would like to put them horizontally shifted next to the red values

Thanks in
advance,

Rosalinde Van Couwenberghe

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