Sentences with phrase «principal components»

Third, it used the exploratory technique of principal components analysis combined with a obscure weighting formula, producing hockey sticks from random data.

Maybe we need to use principal component analysis to tease it out, but we do need to simplify the broad parts of the strategy for testing.

Principal component series can include negative weights, which result in showing a contrast between different series — picture a series with positive weights for finance stocks and negative weights for tech stocks.

Having worked with principal components analysis and statistical modelling in my own work, I can appreciate the funny side.

We made the narrower point that, using correct principal components calculations on their data, they could not conclude that the 1990s were the warmest decade and 1998 the warmest year.

The basic idea behind principal component regression is to replace the predictors (i.e., individual proxies) with a smaller number of objectively determined variables that are linear combinations of the original proxies.

Secondly, we can display the first few principal components for both of the data sets using the transformed unit.

Using centered principal component analysis with the same data you arrive at virtually the same hockey stick.

The 1st principal component accounts for 90 % of the variance of the data, so it dominates the fluctuations.

Comparing just single principal components between two different approaches may be misleading.

In the above discussion, I haven't talked about principal components very much and there's a reason for that.

There are as many principal components as there are original variables.

To minimize multiple testing, we conducted principal components analyses to create summary indices of parent and child behaviors.

It would be better to ignore principal components analysis than to mention it and not give much explanation.

In general, one should judge the set of principal components taken together as a group because they are used together to form a reconstruction.

Each was centered at the mean of its last 100 values, and the first principal component was found.

We used a variant of principal components analysis to generate marital quality profiles, based on one's endorsement of positive and negative marital characteristics.

In principal components discussions, the weights have forbidding names like eigenvectors or empirical orthogonal functions, but, at the end of the day, these are just weights.

These SST and SLP patterns around the North America also appear in the regression maps derived from the leading principal components of total water storage (Fig. 6e, f).

We analyzed the dimensionality of these 40 items using principal component factor analysis.

, Malcolm Baker, Johnathan Wang and Jeffrey Wurgler investigate returns for different types of stocks in the context of broad investor sentiment index derived from principal component analysis of six indicators: trading volume as measured by NYSE turnover; the dividend premium; the closed - end fund discount; the number of, and first - day returns on, Initial Public Offerings; and the equity share in new issues.

They also compare DR - CAPM to optimal models based on principal component analysis within and across asset classes.

A pool of 25 items was chosen to capture the two dimensions (Anxiety and Avoidance), which were obtained through principal components analysis in a sample of 477 adults.

It failed to mention an extremely important inaccuracy in MBH98 description of methods (the significance of which we had discussed at length in our submission): their failure to describe the subtraction of the 1902 - 1980 mean prior to tree ring principal components calculation.

To tease out whether these correlations were due to a small sample size or chance, the researchers used a more sophisticated statistical technique called principal components analysis, testing the actual results against 10,000 randomly generated simulations.

The factor structures of the GHQ - 12 and GHQ - 28 extracted by principal component analysis were compared in participating centres.

Linear metrics (cerebral lobe dimensions and sulcal lengths) and principal component scores of cortical shape variation in 206 chimpanzees and 218 human brains.

MAnnian principal components on the North American tree ring network; then Partial Least Squares regression of NH temperature against the PC1 and other proxies; then re-scaling done a smidge differently.

In particular, their paper indicates that they did principal components on the correlation matrix of short - centered data, whereas MBH98 did singular value decomposition (SVD) on the short - centered data matrix itself.

Mann obviously objected at the time (and subsequently) to reconstructions without bristlecones, with the objections couched in language of retained principal components — that sort of thing.

2) I claimed an argument wasn't new, «the hockey stick was an artifact of the conventions used in applying principal component analysis (PCA).»

I think that many non-academic people, who would be put off by technical questions like the validity of principal components algorithms, may very well be interested in what I have learned about these processes as they apply to modern climate studies.