Re[2]: [tied] Re: Renfrew's theory renamed as Vasco-Caucasian

At 5:02:41 PM on Sunday, September 30, 2007, fournet.arnaud
wrote:

> From: Brian M. Scott


>> However, Arnaud's claim was not that the difference
>> between 100% and 93% retention represents 1500 years, but
>> that the difference between 79% and 72% retention does
>> so. Let x be the time depth in millennia corresponding
>> to 79% retention with rate r; then .79 = r^x, and .72 =
>> r^(x + 1.5) = r^x * r^1.5 = .79 * r^1.5, so r^1.5 =
>> .72/.79. Solving this for r yields a value of r = 0.94,
>> i.e. 94% retention per millennium. With that value of r,
>> 79% retention corresponds to a time depth of a little
>> over 3800 years, and 72% retention to one of a little
>> over 5300 years. This is obviously nonsense.

> I don't understand what you did.

Really? It's mathematically trivial, and basic to the model
that you're trying to use. I suggest not using tools that
you don't understand -- especially ones as dull as naive
glottochronology has proved itsekf to be.

> And I won't assume the calculations and the conclusion.

> I suggest 89 % retention per millenium as a better figure.

Then why didn't you use that figure in your own
calculations? (You needn't answer: the reason is clear
enough from your previous statement.)

Brian