histogram

Hi David,

I have 2 tables, each with several columns and rows of data.  I am
only interested in the data from column 6, which contains values in
the range -PI to PI.  I want to plot the data from tableD with the y
axis denoting percentage with respect to tableR.  So if data points in
the break 2 - 3 appear half as often in tableD as in tableR, the y
axis should show 50 percent.  Does that make sense?
I've been plotting the data like this to date:

hist(tableD[,6],ylab="frequency", xlab="angle")

Thanks a lot for your help



On Mon, Feb 6, 2012 at 1:31 PM, David Winsemius <dwinsemius at comcast.net 

wrote:


On Feb 6, 2012, at 12:23 PM, Francis Keyes wrote:

Thanks.  How do you suggest I use the reference population?   
Sorry, I'm new to R and just don't see it.  If i can get a plot  
that is counts or density relative to my reference data it would  
be ideal.

It is difficult to specify "how" when we have no "what". The "what"  
is your responsibility, not ours. My thought was to use the ratio  
of the results of hist() on the two populations  which would then  
be offered back to hist or barplot. ....which (of course) requires  
that the 'breaks'  be the same. Provide an example of your R  
representations of the reference population and tested population  
and all will become clear.

(And learn to post in plain text, please.)

--
David Winsemius, MD
West Hartford, CT

On Mon, Feb 6, 2012 at 1:12 AM, David Winsemius <dwinsemius at comcast.net 

wrote:

On Feb 5, 2012, at 8:31 PM, Francis Keyes wrote:

With R and the hist function, is there a way to make a histogram  
in which
the y axis denotes propotion with respect to a separate sample  
dataset of
the same range instead of frequency?

hist() returns an object with both "counts" and "density". If you  
had a reference population it should be a fairly simple matter to  
use one or the other of those.