Re: EARLY EVOLUTION OF 'BIRDS'

[Randy King <randyk@ims.com>]

I'm late in my emails again, hope this hasn't been beaten to death
already.  I just can't leave it alone....

At 11:52 PM 11/5/98 EST, Philidor11@aol.com wrote:
>'Say the ratio of maniraptorans living in the K to those living in the J was
>A:B;
>Say the ratio of the chances of an indiv living in the K ever being found to
>that of one in the J is C:D;
>The ratio of the chances of a maniraptoran we have found coming from the K
>to from the J is (A/B)*(C/D).
>The probability of any maniraptoran we have found coming from the K is  1/(1
>+ 1/ ((A/B) * (C/D)) ).

I think this is incorrect.  I believe the ration of maniraptoran in K to J
would be (AC:BD).  The probability of a given maniraptoran coming from K
would be AC/(AC+BD).  The probability of N given maniraptorans coming from K
would be [AC/(AC+BD)]^N.  

>
>The chance of N maniraptoran fossils all appearing after Archaeopteryx is
>this expression raised to the power of N.'

Assuming Archie came from the JK border.  There are too many assumptions
being made to draw definite conclusions.  Starting with, distribution of
creatures we've found from J or K isn't an independent variable, but very
dependent on the geography.  

Where are you trying to go - and who was it that's going??

-Randy, mathematician at large.