RG#26: centepede plot

set.seed(9001)
 p.value <- vector()
 dataf <- as.data.frame(matrix(rep(NA, 2000), nrow=100))
names(dataf) <- c(paste("V",1:19, sep=""), "y")
 for(i in 1:20) {
        dataf[,i] <- rnorm(20, 50, 10)
              }

#plot
require (plotrix)
seg<-get.segs(dataf)

 centipede.plot(seg, main= "A centipede plot",vgrid=c(10))

#adding grids to the plot
grid(nx = 10, ny = 19, col = "gray50")