[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Extinction (of marbles)

From: stevet@shelby.net (Stephen Throop)

 > If you pick a single "survivor" from a box with 100 red marbles and 600
 > others, the odds are 6 to 1 that it won't be red.  ...
 > If you pick 70 (10% survival), odds are about 90 thousand to 1 that you
 > will have a red.  If you pick 175 (25% survival), odds are 44 trillion
 > to 1 that you will have at least one red.
 > Did I figure out the math right?  If I have applied the marble analogy
 > correctly, it sounds as if the KT extinctions were not random.

Well, it is probably close.

However, the question is still not quite right.  You shouldn't be asking
about red specifically, you should be asking what the probability that
*some* color (any color) is missing from the final pick of survivors.
That is the question that corresponds to the "stochastic model".
[Also, you actually need to compute the range of extinction rates
across all colors (clades), and compare that to the range of extinction
rates across the various clades in Archobald's data].

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.