Dear friends. I've made a very simple procedure to make Bland-Altman plots
and it works OK except for the inability to take a variate as argument in
annotation. I'm sure it is a very simple error, so if you have 5 seconds
please tell me.
Best wishes
Troels
bland <- function (x) #accepts two columns
{
mn <- 0.5*(x[,1]+x[,2])
diff <- x[,1]-x[,2]
plot(mn,diff,pch=16,xlab="Mean",ylab="Difference",
main = paste("Bland Altman plot",mn))
abline(h=mean(diff),lty=2)
abline(h=mean(diff)+c(2,-2)*sqrt(var(diff)))
}
Troels
look here:
http://www.wired.com/wired/archive/8.04/joy.html
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Troels Ring <tring at mail1.stofanet.dk> writes:> bland <- function (x) #accepts two columns > { > mn <- 0.5*(x[,1]+x[,2]) > diff <- x[,1]-x[,2] > plot(mn,diff,pch=16,xlab="Mean",ylab="Difference", > main = paste("Bland Altman plot",mn)) > abline(h=mean(diff),lty=2) > abline(h=mean(diff)+c(2,-2)*sqrt(var(diff))) > }Er, what would you want to get? "mn" is a vector with potentially a lot of values in it, so neither paste(..., mn) or paste(...,mn,collapse=",") or anything in that vein looks particularly atttractive. Perhaps ... main = paste("Bland Altman plot of", substitute(x)) ... -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
As Peter helpfully pointed out mn was a vector, so here is the corrected
version:
bland <- function (x) #accepts two columns
{
mn <<- 0.5*(x[,1]+x[,2])
diff <- x[,1]-x[,2]
plot(mn,diff,pch=16,xlab="Mean",ylab="Difference",
main = "Bland Altman plot",
sub= paste("Mean = ",formatC(mean(diff),digits=3)))
abline(h=mean(diff),lty=2)
abline(h=mean(diff)+c(2,-2)*sqrt(var(diff)))
At 14:00 24-04-00, you wrote:>Dear friends. I've made a very simple procedure to make Bland-Altman
plots
>and it works OK except for the inability to take a variate as argument in
>annotation. I'm sure it is a very simple error, so if you have 5 seconds
>please tell me.
>Best wishes
>Troels
>
> bland <- function (x) #accepts two columns
>{
>mn <- 0.5*(x[,1]+x[,2])
>diff <- x[,1]-x[,2]
>plot(mn,diff,pch=16,xlab="Mean",ylab="Difference",
>main = paste("Bland Altman plot",mn))
>abline(h=mean(diff),lty=2)
>abline(h=mean(diff)+c(2,-2)*sqrt(var(diff)))
>}
>Troels
>
>look here:
>http://www.wired.com/wired/archive/8.04/joy.html
>
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>r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
>Send "info", "help", or "[un]subscribe"
>(in the "body", not the subject !) To: r-help-request at
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Troels Ring, MD
Department of Nephrology
Aalborg Hospital, Denmark
tring at mail1.stofanet.dk
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