[R] Boxplot with grouped data

Peter Flom peterflomconsulting at mindspring.com
Thu Oct 22 18:08:28 CEST 2009

Paul Smith <phhs80 at gmail.com> wrote
>Is there some way of drawing a boxplot, with R, when one does not have
>the original continuous data, but only the data grouped in classes?
>The function boxplot() can only deal with original data.

It's not clear how the data are, now.  What are the classes? Are they numbers? 

Let's make something up.  Is this what you have and want?

y <- c(rep("0-10", 5), rep("11-20", 10), rep("21-30", 15))

y <- as.ordered(y)
y <- as.numeric(y)
y[y == 1] <- 5
y[y == 2] <- 15.5
y[y == 3] <- 25.5



Peter L. Flom, PhD
Statistical Consultant
Website: www DOT peterflomconsulting DOT com
Writing; http://www.associatedcontent.com/user/582880/peter_flom.html
Twitter:   @peterflom

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