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# re: EARLY EVOLUTION OF 'BIRDS'

 Eek!  I knew someone would say something like this!--Original Message-- From: Randy King Date: 09 November 199819:19>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 Jwas>>A:B;>>Say the ratio of the chances of an indiv living in the K ever being foundto>>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 is1/(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).But that's the same as (A/B)*(C/D).As for the rest of it, well, you may well be right, I'm not even going tocheck it, because the chances of throwing heads 170 times in a row is stillincredibly small, even with a coin that lands heads 95% of the time.>The probability of a given maniraptoran coming from K>would be AC/(AC+BD).  The probability of N given maniraptorans coming fromK>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.No, I did say much the same applies wherever you take the line, just a slightlydifferent question.>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.It's the same planet!  And nothing's definite in probability - you still endup with another probability.  The two assumptions I make are that,worldwide, the fossilisation llikelihood ratio between J and K is such andsuch (slot in your choice) and the actual number of animals-ratio was(again, make your choice).  I don't think making those assumptions isunreasonable.  The answer is just another probability.>>Where are you trying to go - and who was it that's going??I'm going to prove the maniraptorans are birds - and you're all goingeventually!>-Randy, mathematician at large.BUT - thanks very much for taking the trouble to work through it.Regards,JJ