R help - Nov 2012 - Changing the base of geom_bar in ggplot

Hi,

this is likely very easy to do but I don't find the right terms to search
for the solution. 
I want to show in a bar chart how much different categories deviate from the
average percentage change. 
Thus, in the following example I would like to set the zero line or base or
whatever it is called to the average of the values (=0.82) and the bars
should show the deviation from that, i.e. have the positive length of the
deviation of the value from the average.
I can do that by subtracting the average from each value but I would like to
have the zero line as the average to make it more clear.
How do you change the 'base'-line?

x <- data.frame(val=c(1.5, 3, -1.4, -1, 2), lab=letters[1:5])
ggplot(data=x, aes(x=lab, y=val)) + geom_bar(stat="identity") 

Many thanks for your help!

Best regards,
Werner



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I think your request is internally inconsistent: you want units of percent but
you want to show the average(I assume you intend "mean")?

You can subtract the mean from each value and then divide by the mean, then
subtract 1, then multiply by 100. You inherently lose visibility to what the
mean was, but that is the nature of percentages.
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Werner <pensterfuzzer at yahoo.de> wrote:
>Hi,
>
>this is likely very easy to do but I don't find the right terms to
>search
>for the solution. 
>I want to show in a bar chart how much different categories deviate
>from the
>average percentage change. 
>Thus, in the following example I would like to set the zero line or
>base or
>whatever it is called to the average of the values (=0.82) and the bars
>should show the deviation from that, i.e. have the positive length of
>the
>deviation of the value from the average.
>I can do that by subtracting the average from each value but I would
>like to
>have the zero line as the average to make it more clear.
>How do you change the 'base'-line?
>
>x <- data.frame(val=c(1.5, 3, -1.4, -1, 2), lab=letters[1:5])
>ggplot(data=x, aes(x=lab, y=val)) + geom_bar(stat="identity") 
>
>Many thanks for your help!
>
>Best regards,
>Werner
>
>
>
>--
>View this message in context:
>http://r.789695.n4.nabble.com/Changing-the-base-of-geom-bar-in-ggplot-tp4651407.html
>Sent from the R help mailing list archive at Nabble.com.
>
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