I am running the code below and receiving NA's in many of the boxes that are supposed to contain r values. Could anyone tell me what that means? and possibly how to fix it? Thanks, EGB panel.cor <- function(x, y, digits=2, prefix="", cex.cor, ...) { usr <- par("usr"); on.exit(par(usr)) par(usr = c(0, 1, 0, 1)) r <- abs(cor(x, y)) txt <- format(c(r, 0.123456789), digits=digits)[1] txt <- paste(prefix, txt, sep="") if(missing(cex.cor)) cex.cor <- 0.8/strwidth(txt) text(0.5, 0.5, txt, cex = cex.cor * r) } panel.hist <- function(x, ...) { usr <- par("usr"); on.exit(par(usr)) par(usr = c(usr[1:2], 0, 1.5) ) h <- hist(x, plot = FALSE) breaks <- h$breaks; nB <- length(breaks) y <- h$counts; y <- y/max(y) rect(breaks[-nB], 0, breaks[-1], y, col="cyan", ...) } panel.diagonalLine <- function (x, y, col = par("col"), bg = NA, pch par("pch"), cex = 1, col.diagLine = "red", ...) { points(x, y, pch = pch, col = col, bg = bg, cex = cex) ok <- is.finite(x) & is.finite(y) if (any(ok)) abline(a=0, b=1, col=col.diagLine) } panel.lmLine <- function (x, y, col = par("col"), bg = NA, pch par("pch"), cex = 1, col.diagLine = "red", ...) { points(x, y, pch = pch, col = col, bg = bg, cex = cex) ok <- is.finite(x) & is.finite(y) if (any(ok)) g <- lm(y~x) abline(g, col=col.diagLine) } [[alternative HTML version deleted]]