Re: Histogram chart - What do the y-axis numbers mean?

["Andreas J. Guelzow" <aguelzow math concordia ab ca>]

On Fri, 2008-09-12 at 15:28 -0400, Marlon Nelson wrote:
> Thank you, Jean
> 
> Another question:  The data table was produced using the Histogram
> tool.  The 1% bin counts 1011 data points between -1% and 1%.  In the
> chart of the histogram, the area representing those points falls
> between 1% and 3% on the x-axis.  Seems like an off-by-one problem to
> me.

Hi

please file a report at bugzilla.gnome.org. I will be rewriting the
histogram _tool_ soon so then I am reminded of that issue.

Thanks

Andreas

> 
> On Fri, Sep 12, 2008 at 11:17 AM, Jean Bréfort <jean brefort free fr> wrote:
> > Le vendredi 12 septembre 2008 à 10:46 -0400, Marlon Nelson a écrit :
> >> I originally thought this was a bug and was about 30 seconds from
> >> submitting one to bugzilla when I began to suspect the problem is with
> >> my understanding of what a histogram is.
> >>
> >> With the data listed below (frequency of daily returns of Merrill
> >> Lynch stock over the last 10 years), I created a histogram chart.  The
> >> highest point on the chart reaches 50,000.  I was expecting 1011.
> >>
> >> Reading a bit from wikipedia, I see what I was actually expecting to
> >> see is a bar chart.
> >>
> >> But given a histogram chart of this data, what do the y-axis numbers mean?
> >>
> >> Bin   Frequency
> >> -15%  1
> >> -13%  1
> >> -11%  4
> >> -9%   6
> >> -7%   13
> >> -5%   53
> >> -3%   167
> >> -1%   510
> >> 1%    1011
> >> 3%    489
> >> 5%    156
> >> 7%    57
> >> 9%    26
> >> 11%   6
> >> 13%   4
> >> 15%   3
> >> 17%   2
> >>
> >> --
> >> -eom-
> >
> > The histogram plots the density, as the 1011 data are in a 0.02
> > interval, you get 1011 / 0.02 = 50550 as the largest value.
> >
> > Regards,
> > Jean
> >
> >
> 
> 
>