[R] Questions about histograms

[Andre Nathan]

Thanks Bill and Duncan for your replies, I understand it now. Somehow I
didn't notice the width of the bars was < 1.0.

Andre

On Mon, 2008-02-11 at 11:38 +1000, Bill.Venables at csiro.au wrote:
> Andre,
> 
> Regarding your first question, it is by no means clear there is anything
> to fix, in fact I'm sure there is nothing to fix.  The fact that the
> height of any bar is greater than one is irrelevant - the width of the
> bar is much less than one, as is the product of height by width.  Area
> is height x width, not just height....
> 
> Regarding the second question - logarithmic breaks.  I'm not aware of
> anything currently available to do this, but the tools are there for you
> to do it yourself.  The 'breaks' argument to hist allows you to specify
> your breaks explicitly (among other things) so it's just a matter of
> setting up the logarithmic (or, more precisely, 'geometric progression')
> bins yourself and relaying them on to hist.
> 
>  
> 
> 
> Bill Venables
> CSIRO Laboratories
> PO Box 120, Cleveland, 4163
> AUSTRALIA
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> 
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Andre Nathan
> Sent: Monday, 11 February 2008 11:14 AM
> To: r-help at r-project.org
> Subject: [R] Questions about histograms
> 
> Hello
> 
> I'm doing some experiments with the various histogram functions and I
> have a two questions about the "prob" option and binning.
> 
> First, here's a simple plot of my data using the default hist()
> function:
> 
> > hist(data[,1], prob = TRUE, xlim = c(0, 35))
> 
>   http://go.sneakymustard.com/tmp/hist.jpg
> 
> My first question is regarding the resulting plot from hist.scott() and
> hist.FD(), from the MASS package. I'm setting prob to TRUE in these
> functions, but as it can be seen in the images below, the value for the
> first bar of the histogram is well above 1.0. Shouldn't the total area
> be 1.0 in the case of prob = TRUE?
> 
> > hist.scott(data[,1], prob = TRUE, xlim=c(0, 35))
> 
>   http://go.sneakymustard.com/tmp/scott.jpg
> 
> > hist.FD(data[,1], prob = TRUE, xlim=c(0, 35))
> 
>   http://go.sneakymustard.com/tmp/FD.jpg
> 
> Is there anything I can do to "fix" these plots?
> 
> My second question is related to binning. Is there a function or package
> that allows one to use logarithmic binning in R, that is, create bins
> such that the length of a bin is a multiple of the length of the one
> before it?
> 
> Pointers to the appropriate docs are welcome, I've been searching for
> this and couldn't find any info.
> 
> Best regards,
> Andre
> 
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