Linked Questions

1 vote
0 answers
3k views

I am confused as to why eigenvalues are the principal components. What is the intuition behind finding the eigenvectors of the covariance matrix for PCA?
random0620's user avatar
4 votes
0 answers
2k views

I am trying to enhance the contrast in the images I get after scanning a surface using Thermography (Principal Component Thermography ~Rajic, which is basically an application of Principal Component ...
Rumi-Thermo's user avatar
1 vote
1 answer
379 views

I've been studying PCA, and some of the terminology isn't very clear. I do not understand what they mean when they refer to a "principal component". One definition I have seen calls it the new ...
user167923's user avatar
2 votes
0 answers
54 views

I am confused with the terminologies of score and principal component in PCA, it seems they are equivalent but there is also some difference. Could anyone explain to me?
user93892's user avatar
  • 365
639 votes
5 answers
536k views

Principal component analysis (PCA) is usually explained via an eigen-decomposition of the covariance matrix. However, it can also be performed via singular value decomposition (SVD) of the data matrix ...
amoeba's user avatar
  • 109k
113 votes
5 answers
247k views

In principal component analysis (PCA), we get eigenvectors (unit vectors) and eigenvalues. Now, let us define loadings as $$\text{Loadings} = \text{Eigenvectors} \cdot \sqrt{\text{Eigenvalues}}.$$ I ...
user2696565's user avatar
  • 1,439
17 votes
1 answer
11k views

I'm currently going through a slide set I have for "factor analysis" (PCA as far as I can tell). In it, the "fundamental theorem of factor analysis" is derived which claims that the correlation ...
user2249626's user avatar
8 votes
2 answers
26k views

I am looking at this link http://strata.uga.edu/8370/lecturenotes/principalComponents.html where it says In interpreting the principal components, it is often useful to know the correlations of ...
user3022875's user avatar
7 votes
2 answers
4k views

Principal component regression (PCR) in fact is regression on PC scores but not PCs. Why then in so many books and tutorials do they say something like, in statistics, principal component ...
mingzuheng's user avatar
7 votes
1 answer
10k views

I have performed principal component analysis (PCA) of data matrix $X$ by doing singular value decomposition (SVD) $$ X = U S V', $$ where the columns of $V$ are the principal directions/axes and the ...
Jamgreen's user avatar
  • 393
3 votes
1 answer
5k views

I often see the principal components of PCA described as "linear combinations of the original features". Say we want to compute the principal components of our $m \times n$ design matrix $A$ ($m$ ...
cangrejo's user avatar
  • 2,289
2 votes
1 answer
2k views

I am very new to R and statistics so this may be a simple question. I have a matrix (1000,756) containing 1000 years of winter sea-level pressure data (SLP) at 756 locations in the North Atlantic. I ...
Edward Armstrong's user avatar
0 votes
1 answer
949 views

I see that in PCA the first principal component maximizes the variances amongst all the points within the data set. What exactly does this mean, what does it show and what does every other principal ...
ryan's user avatar
  • 1
2 votes
1 answer
126 views

Are principal factors in principal component analysis always uncorrelated, or can they end up being correlated? If so, how and why?
Nickpick's user avatar
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