Comments on: Titan TV’s short piece on the Heartland Conference http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/ "All manner of statistical analyses cheerfully undertaken." Fri, 21 Nov 2008 10:45:54 +0000 http://wordpress.org/?v=2.3.3 By: TCO http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-4801 TCO Mon, 05 May 2008 01:42:15 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-4801 1. The humor was well done, gentle. 2. I'm bummed that you went to the Heartland Conference. Please tell me that you thought Watts and such to be poor thinkers. 1. The humor was well done, gentle.

2. I’m bummed that you went to the Heartland Conference. Please tell me that you thought Watts and such to be poor thinkers.

]]> By: Briggs http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1137 Briggs Sun, 09 Mar 2008 12:52:54 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1137 All, I will get to the PCA stuff in a little bit. It's very easy to be confused by these things, and even when they are used perfectly correctly, they do not always mean what you think they do (how's that for confusing!). See today's post for more confusion. Briggs All,

I will get to the PCA stuff in a little bit. It’s very easy to be confused by these things, and even when they are used perfectly correctly, they do not always mean what you think they do (how’s that for confusing!).

See today’s post for more confusion.

Briggs

]]> By: anon http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1108 anon Sat, 08 Mar 2008 07:30:18 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1108 William, it looks to me like a two by two matrix. But I do not understand this stuff properly. It seems like we have a time series which may or may not contain a trend. We apply PCA using the mean of a subset of the series, rather than the mean of the series. I don't actually understand how to calculate PCA, so I am not sure what this really means. Then there seem to be four possibilities: the data has a trend and DPCA either picks it correctly or wrongly fails to pick it. It has no trend, and DPCA wrongly shows one anyway, or else correctly says it has no trend. Don't know if I understand the debate at all, but one question seems to be whether using the mean of a subset of the series makes a difference to the answer in some, or in all, of the above four cases. William, it looks to me like a two by two matrix. But I do not understand this stuff properly.

It seems like we have a time series which may or may not contain a trend.

We apply PCA using the mean of a subset of the series, rather than the mean of the series. I don’t actually understand how to calculate PCA, so I am not sure what this really means. Then there seem to be four possibilities: the data has a trend and DPCA either picks it correctly or wrongly fails to pick it. It has no trend, and DPCA wrongly shows one anyway, or else correctly says it has no trend.

Don’t know if I understand the debate at all, but one question seems to be whether using the mean of a subset of the series makes a difference to the answer in some, or in all, of the above four cases.

]]> By: anon http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1106 anon Sat, 08 Mar 2008 06:15:25 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1106 http://tamino.wordpress.com/2008/03/06/pca-part-4-non-centered-hockey-sticks/ is the current case. The Wegman report was another: http://www.climateaudit.org/pdf/others/07142006_Wegman_Report.pdf http://www.uoguelph.ca/~rmckitri/research/StupakResponse.pdf http://www.uoguelph.ca/~rmckitri/research/McKitrick-hockeystick.pdf s a lay account of the issue. See also http://www.uoguelph.ca/~rmckitri/research/PCnotes.pdf I really cannot get to the bottom of this thing. Decentered PCA, data mining and so on. Eigenvalues! Help! Cheers. http://tamino.wordpress.com/2008/03/06/pca-part-4-non-centered-hockey-sticks/

is the current case. The Wegman report was another:

http://www.climateaudit.org/pdf/others/07142006_Wegman_Report.pdf
http://www.uoguelph.ca/~rmckitri/research/StupakResponse.pdf

http://www.uoguelph.ca/~rmckitri/research/McKitrick-hockeystick.pdf

s a lay account of the issue. See also

http://www.uoguelph.ca/~rmckitri/research/PCnotes.pdf

I really cannot get to the bottom of this thing. Decentered PCA, data mining and so on. Eigenvalues! Help!

Cheers.

]]> By: Briggs http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1096 Briggs Fri, 07 Mar 2008 20:48:56 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1096 Anon, I'd be happy to post something about principal components analysis. Do you have a specific link in mind where examples are being used? Briggs Anon,

I’d be happy to post something about principal components analysis. Do you have a specific link in mind where examples are being used?

Briggs

]]> By: anon http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1094 anon Fri, 07 Mar 2008 17:21:28 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1094 William, many of us are hopelessly confused and still more hopelessly uninformed about PCA. Right now there is an interesting correspondence going on on Tamino about MBH and the McIntyre analysis of MBH, not to mention Wegman's endorsement of MM..... Do you have time to write a simple authoritative explanation of what has been done by who and who is right and who is wrong? You will be doing us all an immense favor if you can. William, many of us are hopelessly confused and still more hopelessly uninformed about PCA. Right now there is an interesting correspondence going on on Tamino about MBH and the McIntyre analysis of MBH, not to mention Wegman’s endorsement of MM…..

Do you have time to write a simple authoritative explanation of what has been done by who and who is right and who is wrong? You will be doing us all an immense favor if you can.

]]> By: erik http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1070 erik Thu, 06 Mar 2008 18:36:55 +0000 http://wmbriggs.com/blog/2008/03/05/titan-tvs-short-piece-on-the-heartland-conference/#comment-1070 I thought that was actually pretty funny. It was an obvious "Colbert" riff, but in that context the conference came off looking pretty good. I thought that was actually pretty funny. It was an obvious “Colbert” riff, but in that context the conference came off looking pretty good.

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