number of observations used in scatterplot.matrix()

Hi Luciano,

Thank you for your suggestion. However I'm afraid it will not work,
since the actual number of observations used by cor.test() is not the
total number of observations (nrow(x)) ?I have.
cor.test() omits observations with NAs in x or in y, which do actually
occur in my data sets.

Kind regards,

Dulce


El 21/01/2011 16:13, Luciano Selzer escribi?:

Hi, maybe something like this should do the trick:
? ? ? ? ? n <- nrow(x)

? ? ? ? ? ? txt <- paste("rho=", txt, "\np=",pval, "n=", n, sep="")


HTH
Luciano


2011/1/21 Maria Dulce Subida <mdsubida at icman.csic.es
<mailto:mdsubida at icman.csic.es>>

? ? Dear all,

? ? I have a script (please see below) that gives a scatter plot matrix on
? ? the upper panel, and the spearman rho and probability values on the
? ? lower panel. It also gives the density function of each variable
? ? in the
? ? diagonal, adds a smoother and a linear regression line to each scatter
? ? plot, and puts significant spearman coefficient values in red.
? ? Now I would like to add to the lower panel information, the value of
? ? n=number of observations used to calculate the spearman correlation
? ? coefficient. Does anyone know I could I add that parameter to my
? ? function panel.cor?

? ? Thank you!

? ? Kind regards,

? ? Dulce

? ? ################

? ? panel.cor <- function (x, y,method="spearman",digits=2,...)
? ? {
? ? ? ? ? ? points(x,y,type="n");
? ? ? ? ? ? usr <- par("usr"); on.exit(par(usr))
? ? ? ? ? ? par(usr = c(0, 1, 0, 1));
? ? ? ? ? ? correl <- cor.test(x, y,method=method);
? ? ? ? ? ? r=correl$estimate;
? ? ? ? ? ? pval=correl$p.value;
? ? ? ? ? ? color="black";
? ? ? ? ? ? if (pval<0.05) color="red";
? ? ? ? ? ? txt <- format(r,digits=2)
? ? ? ? ? ? pval <- format(pval,digits=2)

? ? ? ? ? ?n <- nrow(x)

? ? ? ? ? ? txt <- paste("rho=", txt, "\np=",pval, "n=", n, sep="")
? ? ? ? ? ? text(0.5, 0.5, txt,col=color)
? ? }

? ? scatterplot.matrix (~ var1 + var2 + var3 , data=mydata,
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? main="Mydata", smooth=TRUE,
? ? lower.panel=panel.cor, pch=20, cex=0.5,
? ? col=c("red","black"),cex.labels=1, font.labels=2, lwd=0.5)





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