[R] histogram

[Roslina Zakaria]

Hi r-expert,
I would like to plot histogram using frequency not density.
But I got the following warning.
 obs.hist <- hist(jan_data2[,4],right=FALSE,breaks=c(0,5,10,15,20,100),freq=TRUE,
+             xlab="Rain amt (mm)",ylim=c(0,3000),
+             main="Frequency of observed, Jan (1901-1990), Pooraka")
Warning message:
In plot.histogram(r, freq = freq1, col = col, border = border, angle = angle,  :
  the AREAS in the plot are wrong -- rather use freq=FALSE

I don't really understand the warning message and hope anybody can help me.
Thanks in advance for your help.