[R] Quantitative analysis of non-standard scatter plots.

Firas Swidan, PhD frsswdn at gmail.com
Wed Jul 23 19:52:56 CEST 2008

How do I check that, and what quantification does it provide?

On Wed, 2008-07-23 at 21:20 +0530, Bogaso Cristofer wrote:
> Have u checked skewness of data?
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of Firas Swidan
> Sent: 23 July 2008 18:38
> To: r-help at r-project.org
> Subject: [R] Quantitative analysis of non-standard scatter plots.
> Hi,
> I am having difficulties in finding ways to analyse scatter plots and
> quantitatively differentiate between them. Since this is best demonstrated
> by a figure, I have attached one with 4 subfigures (a)-(d). Qualitatively
> (and I hope you would agree with me), sub-figures (a), (b), and (d) seem to
> represent uniform 2d scatters. It is hard for me to quantify it, but it
> seems as if the envelopes (max values of y-axis) are independent of the
> values of the x-axis. Sub-figure (c), on the other hand, exhibits a
> different behaviour, as the envelope seems to expand as the x-values
> increase (at least till some threshold, and with the exception of a single
> outlier toward the begining of the x-axis). My question is how can I verify
> the above observation quantitatively, and does R provide the required tools
> for doing so? I have tried to perform linear fittings and to claim that the
> slope of the fitted line in (c) is more significant than the lines in (a),
> (b), and (d), but this does not seem convincing to me. Are there standard
> toolboxes for such cases?
> Thanks for any suggestions / tips,
> Firas.
Firas Swidan, PhD
Founder and CEO
Olymons: Blessing Machines with Vision (TM)
P.O.Box 8125
Nazareth 16480
Cell: +.972.(0)54.733.1788

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