Tag Archives: weights

Squared Weights in MBH98

A couple of weeks ago, I said that I would document (at least for Jean S and UC) an observation about the use of squared weights in MBH98. I realize that most readers won’t be fascinated with this particular exposition, but indulge us a little since this sort of entry is actually a very useful […]

PC Weights on a Square Region

A few days ago, I showed some plots showing distribution of weights arising from principal components carried out on data from a region arranged as a line segment (think Chile). Today I’ve done a similar analysis for a square shaped region again assuming spatial autocorrelation governed by distance. In this case, I made a regular […]

Tamino and the Magic Flute

Tamino has recently re-iterated the climate science incantation that Mann’s results have been “verified”. He has done so in the face of the fact that one MBH98 claim after another has been shown to be false. In some cases, the claim has not only been shown to be false, but there is convincing evidence that […]

Rule N and Weighted Regression

Today’s post, which has a forbidding title, contains an interesting mathematical and statistical point which illuminates the controversy over how many PCs to retain. In my re-visiting the totally unknown corner of Mannian methodology – regression weights and their determination – I re-parsed the source code, finding something new and unexpected in Mannian methodology and […]

Bilge in Tamino's Canoe

In order to illustrate a useful application of principal components, Tamino showed coordinate systems for the motion of a canoe. In the context of MBH, it would have been more instructive to show how principal components apply to tree ring networks than to canoes. In such a context,a non-Mannian centered PC1 will typically show some […]

"Mannian" PCA Revisited #1

One of Hansen’s pit bulls, Tamino, has re-visited Mannian principal components. Tamino is a bright person, whose remarks are all too often marred by the pit bull persona that he has unfortunately chosen to adopt. His choice of topic is a curious one, as he ends up re-opening a few old scabs, none of which […]

Another Assignment for the EAS8001 Mission Impossible Team

Mission Impossible Team, here’s your assignment today. Unfortunately you failed your last assignment: replicating Mann’s claimed correlations. But that probably was impossible. Today your assignment is probably possible, but is a dangerous expedition into the dark underground – into the terrifying world of Mannian RegEM. Courage and perseverance will be required. You may not return […]

A New Spaghetti Graph

Von Storch and Mann have both said that, in an MBH98-type reconstruction, it is impossible to allocate the impact of individual proxies. This is incorrect as we pointed out in MM05b. My posts on MBH98 Linear Algebra showed this more clearly (or at least in more detail). However, those posts only took the analysis back […]


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