[R] plotting a distribution curves
Richard A. O'Keefe
ok at cs.otago.ac.nz
Thu Sep 4 05:06:02 CEST 2003
Rajarshi Guha <rajarshi at presidency.com> wrote:
is there a way to plot distribution curves (say normal or chi sq etc)
from within R?
For example I looked up the *chisq family of functions but I'm not sure
as to how I would use them to generate a plot of the chi sq distribution
(for arbitrary d.o.f).
Perhaps the most obvious way:
x <- seq(0, 30, length=101)
plot(x, dchisq(x, df=8))
Another way:
curve(dchisq(x,df=8), from=0, to=30)
As someone has recently noted, code that depends on the textual
form of something is often subtly wrong, which is why I think that
"curve" and similar functions are best avoided. A third way that
is better than "curve" is
plot(function(x) dchisq(x,df=8), from=0, to=30)
in which the name of the argument x no longer matters.
This can of course be used with any function, not just a c* function.
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