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Groups > comp.lang.python > #36357

Re: Numpy outlier removal

From Robert Kern <robert.kern@gmail.com>
Subject Re: Numpy outlier removal
Date 2013-01-07 15:35 +0000
References <mailman.179.1357501521.2939.python-list@python.org> <50ea28e7$0$30003$c3e8da3$5496439d@news.astraweb.com> <mailman.205.1357525775.2939.python-list@python.org> <50ea58f0$0$21851$c3e8da3$76491128@news.astraweb.com> <CAHVvXxSiS3TvtccX7VZyPE1+HyZXFs51jsDC-mn5BG2MUhji3g@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.224.1357572924.2939.python-list@python.org> (permalink)

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On 07/01/2013 15:20, Oscar Benjamin wrote:
> On 7 January 2013 05:11, Steven D'Aprano
> <steve+comp.lang.python@pearwood.info> wrote:
>> On Mon, 07 Jan 2013 02:29:27 +0000, Oscar Benjamin wrote:
>>
>>> On 7 January 2013 01:46, Steven D'Aprano
>>> <steve+comp.lang.python@pearwood.info> wrote:
>>>> On Sun, 06 Jan 2013 19:44:08 +0000, Joseph L. Casale wrote:
>>>>
>>>> I'm not sure that this approach is statistically robust. No, let me be
>>>> even more assertive: I'm sure that this approach is NOT statistically
>>>> robust, and may be scientifically dubious.
>>>
>>> Whether or not this is "statistically robust" requires more explanation
>>> about the OP's intention.
>>
>> Not really. Statistics robustness is objectively defined, and the user's
>> intention doesn't come into it. The mean is not a robust measure of
>> central tendency, the median is, regardless of why you pick one or the
>> other.
>
> Okay, I see what you mean. I wasn't thinking of robustness as a
> technical term but now I see that you are correct.
>
> Perhaps what I should have said is that whether or not this matters
> depends on the problem at hand (hopefully this isn't an important
> medical trial) and the particular type of data that you have; assuming
> normality is fine in many cases even if the data is not "really"
> normal.

"Having outliers" literally means that assuming normality is not fine. If 
assuming normality were fine, then you wouldn't need to remove outliers.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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Thread

Numpy outlier removal "Joseph L. Casale" <jcasale@activenetwerx.com> - 2013-01-06 19:44 +0000
  Re: Numpy outlier removal Hans Mulder <hansmu@xs4all.nl> - 2013-01-06 23:33 +0100
    RE: Numpy outlier removal "Joseph L. Casale" <jcasale@activenetwerx.com> - 2013-01-06 22:50 +0000
    Re: Numpy outlier removal MRAB <python@mrabarnett.plus.com> - 2013-01-06 23:18 +0000
  Re: Numpy outlier removal Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-07 01:46 +0000
    Re: Numpy outlier removal "Paul Simon" <psimon@sonic.net> - 2013-01-06 18:21 -0800
    Re: Numpy outlier removal Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-01-07 02:29 +0000
      Re: Numpy outlier removal Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-07 05:11 +0000
        Re: Numpy outlier removal Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-01-07 15:20 +0000
          [Offtopic] Line fitting [was Re: Numpy outlier removal] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-07 17:58 +0000
            Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Chris Angelico <rosuav@gmail.com> - 2013-01-08 06:43 +1100
              Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-08 02:06 +0000
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Chris Angelico <rosuav@gmail.com> - 2013-01-08 17:35 +1100
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Robert Kern <robert.kern@gmail.com> - 2013-01-08 15:55 +0000
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Chris Angelico <rosuav@gmail.com> - 2013-01-09 07:14 +1100
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-09 07:50 +0000
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Robert Kern <robert.kern@gmail.com> - 2013-01-08 22:59 +0000
            Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-01-07 22:32 +0000
              Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-08 01:23 +0000
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Terry Reedy <tjreedy@udel.edu> - 2013-01-08 04:07 -0500
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Maarten <maarten.sneep@knmi.nl> - 2013-01-08 08:47 -0800
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Maarten <maarten.sneep@knmi.nl> - 2013-01-08 08:47 -0800
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-09 00:02 +0000
                Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-01-08 13:50 +0000
            Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Jason Friedman <jason@powerpull.net> - 2013-01-08 19:22 -0700
            Re: [Offtopic] Line fitting [was Re: Numpy outlier removal] Jason Friedman <jason@powerpull.net> - 2013-01-08 19:23 -0700
        Re: Numpy outlier removal Robert Kern <robert.kern@gmail.com> - 2013-01-07 15:35 +0000
    RE: Numpy outlier removal "Joseph L. Casale" <jcasale@activenetwerx.com> - 2013-01-07 02:12 +0000

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