[Offtopic] Line fitting [was Re: Numpy outlier removal]

Robert Kern robert.kern at gmail.com
Tue Jan 8 23:59:06 CET 2013

On 08/01/2013 20:14, Chris Angelico wrote:
> On Wed, Jan 9, 2013 at 2:55 AM, Robert Kern <robert.kern at gmail.com> wrote:
>> On 08/01/2013 06:35, Chris Angelico wrote:
>>> ... it looks
>>> quite significant to show a line going from the bottom of the graph to
>>> the top, but sounds a lot less noteworthy when you see it as a
>>> half-degree increase on about (I think?) 30 degrees, and even less
>>> when you measure temperatures in absolute scale (Kelvin) and it's half
>>> a degree in three hundred.
>> Why on Earth do you think that the distance from nominal surface
>> temperatures to freezing much less absolute 0 is the right scale to compare
>> global warming changes against? You need to compare against the size of
>> global mean temperature changes that would cause large amounts of human
>> suffering, and that scale is on the order of a *few* degrees, not hundreds.
>> A change of half a degree over a few decades with no signs of slowing down
>> *should* be alarming.
> I didn't say what it should be;

Actually, you did. You stated that "a ~0.6 deg increase across ~30 years [is 
h]ardly statistically significant". Ignoring the confusion between statistical 
significance and practical significance (as external criteria like the 
difference between the nominal temp and absolute 0 or the right criteria that I 
mentioned has nothing to do with statistical significance), you made a positive 
claim that it wasn't significant.

> I gave three examples.

You gave negligently incorrect ones. Whether your comments were on topic or not, 
you deserve to be called on them when they are wrong.

> And as I said,
> this is not the forum to debate climate change; I was just using it as
> an example of statistical reporting.
> Three types of lies.

FUD is a fourth.

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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