X-Message-Number: 29008
Date: Tue, 23 Jan 2007 17:02:59 +0300
From: Igor Artyuhov <>
Subject: Re: To all fellow statistic tragics out there (CryoNet #28999...
References: <>

The trick is in using the quadratic trend model instead of the much more 
obvious exponential trend. If one used the latter, he'll obtain for 
membership forecasts something like (a very rough estimate!)

M2024 = M2004*( M2004/M1984) = 476*476/16 = 14161

(instead of 1512.65 for quadratic trend) and

M2044 = M2004*( M2004/M1984)^2 = 476^3/16^2 = 421289.75

(instead of 3378.32).

As well, for patients' number we have

P2024 = P2004*( P2004/P1984) = 68^2/2 = 2312

(instead of 211.415) and

P2044 = P2004*( P2004/P1984)^2 = 68^3/4 = 78608

(instead of 461.802).

It should be kept in mind that any such projections are applicable only 
for a reasonably short forecast time   in any case, it shouldn't be 
comparable with the base period (in our case it is 2004-1975=29 years). 
So, any extrapolation for as much as 2050-2024=26 years is absolutely 
unsupported. We can use it to forecast numbers for up to, say, 2010; the 
exponential trend model will provide more reasonable forecasts than the 
quadratic trend, but both outcomes will be close.

And the last remark: There is no such thing as correlation between 
values unless both of them are stochastic ones. That is, you can 
formally calculate the "correlation" between CI membership and, say, the 
position of Saturn on the sky for last ~10 years   and it will be close 
to 1!   but it would give us no usable information at all.

Happy eternity,
Igor Artyuhov.

| Message #28999
| From: "marta sandberg" <>
| Subject: To all fellow statistic tragics out there 
| Date: Mon, 22 Jan 2007 11:55:31 +0800
| 
| I am a sucker for statistics and I came across this site when browsing.
| http://cryonics.home.att.net/CI/ciprojection.html
| I believe it was compiled by Brent Fox.
| If there is any fellow statistic tragics out there, give it a go.

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