plots boxplot, stripchart and mean

## CAN BE REPLACED BY qplot in ggplot2 package

qplot(x,y,geom=c("boxplot","jitter"))


## plots boxplot, stripchart and mean

boxjitter = function(x,y=NULL,border='gray',jitter=.1,vertical=T,...)
{
  if(!is.null(y))
  {
    boxplot(y~x,border=border,ylim = range(y,na.rm=T),outline=F,...)
    stripchart(y~x,vertical=vertical,method="jitter",jitter=jitter,add=T)
    meanvec = tapply(y,x,mean.na)
    points(1:length(meanvec),meanvec,pch="M",col='blue')
  } else
  {
    x = x[!is.na(x)]
    boxplot(x,border=border,ylim = range(x),outline=F,...)
    stripchart(x,vertical=vertical,method="jitter",jitter=jitter,add=T)
    points(1,mean.na(x),pch="M",col='blue')
  }
}