Re: "But What About The..." arguments (long!)

["philidor11" <philidor11@snet.net>]

<I do think that when there's that huge impact, there should be a huge
catastrophic mass extinction. Such a mass extinction is present. So it
should IMNSHO be the null hypothesis that everything that dies out then does
so because of the impact, and the burden of proof is on those that want to
take something out of this picture, as HP John Bois apparently tries to.>

Because the null hypothesis comes up in discussion sometimes, defining it
seems worthwile:

Quoting from:

http://davidmlane.com/hyperstat/A29337.html


Consider a researcher interested in whether the time to respond to a tone is
affected by the consumption of alcohol. The null hypothesis is that µ1 - µ2
= 0 where µ1 is the mean time to respond after consuming alcohol and µ2 is
the mean time to respond otherwise. Thus, the null hypothesis concerns the
parameter µ1 - µ2 and the null hypothesis is that the parameter equals zero.

The null hypothesis is often the reverse of what the experimenter actually
believes; it is put forward to allow the data to contradict it. In the
experiment on the effect of alcohol, the experimenter probably expects
alcohol to have a harmful effect. If the experimental data show a
sufficiently large effect of alcohol, then the null hypothesis that alcohol
has no effect can be rejected.


I like to say that the null hypothesis is that nothing happened.
Your hypothesis might be restated as:  nothing but the bolide caused the KT
extinctions.  If any factor other than the bolide produced a substantial
portion of the extinctions, then your hypothesis would be falsified.
Hence you have to refute, not just rebut, any other factor educed.
Put another way, your null hypothesis would be that a number of factors
including the bolide caused the extinctions, and you would have to eliminate
each addition to the bolide.
Sounds like a lot of work.

Note, by the way, that in the experiment described the writer is assuming
that all other possible factors are held constant in each group.  Frankly,
as someone who has worked with samples, that's not an easy thing to do,
mostly because you don't know what factors might skew a sample.  Just as
examples, there are different tolerances for alcohol and mood and physical
condition does affect response to sound.  With the weaknesses of the fossil
record, I have an innate suspicious response about your hypothesis.  Nothing
about your knowledge of the record, just an experienced sense of the traps
in the unknown.