David Tyler wrote (using an e-mail client that doesn't wrap lines):
> I am using an older version of R (1.6.2) to run a Monte Carlo
>> simulation, generating 10,000 samples per 'run'. When I plot
> histograms I get the expected 'bins' on the x-axis and the
> frequency distribution on the y-axis. However when I ask R
> to plot the SAME data set with a density curve the x-axis
> emains the same but the y-axis can generate values of up to 1e8 etc.
> Can anyone (a) explain why this might be so and/or (b) suggest a fix?
try
hist(..., freq=FALSE)
This should give the same numbers as the density plots' y-axes.
It sounds like you've got a narrow range of x-axis values (small
numbers, or small differences between them, or both). The total area
under a density estimate curve must equal 1 by definition, so nothing's
really "broken". The only fix is to re-scale the x axis to different
units, or draw a different y-axis on after the fact. Something like...
foo <- density(...)
plot(foo, yaxt="n")
axis(...) # something that means something to you here.
Since this isn't a density plot any longer, it would help to be clear to
your readers what's going on with the plots.
Hope that helps
Cheers
Jason
--
Indigo Industrial Controls Ltd.
http://www.indigoindustrial.co.nz
64-21-343-545
jasont at indigoindustrial.co.nz