[R] histogramm?

Rolf Turner rolf at math.unb.ca
Wed Jun 1 13:26:59 CEST 2005


Gavin Simpson wrote:

	<snip>

>      freq: logical; if 'TRUE', the histogram graphic is a representation
>            of frequencies, the 'counts' component of the result; if
>            'FALSE', _relative_ frequencies ("probabilities"), component
>            'density', are plotted.   Defaults to 'TRUE' _iff_ 'breaks'
>            are equidistant (and 'probability' is not specified).
> 
> So freq = FALSE plots relative frequencies (probabilities).

	Careful! You left out the quote marks on ``probabilities''.
	These are ***CRUCIAL*** inasmuch as the values are NOT
	probabilities, but rather probability ***densities***.
	Which, as I recall Bill Venables once pointed out to me, is
	the only thing that makes sense.  If you are doing a
	histogram, you are looking at a continuous random variable.
	If the variate in question is discrete, so that you
	***really*** want probabilities, you should be doing a
	barplot.

				cheers,

					Rolf Turner
					rolf at math.unb.ca




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