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Principal component analysis (PCA) is a linear dimensionality reduction technique. It reduces a multivariate dataset to a smaller set of constructed variables preserving as much information (as much variance) as possible. These variables, called principal components, are linear combinations of the input variables.

3 votes
1 answer
3k views

Eigenvectors corresponding to eigenvalues

In R, the eigen() returns descending sorted eigenvalues. However, the eigenvectors do not correspond to these sorted eigenvalues. How do I identify the eigenvector corresponding to the ith sorted eige …
Ram Ahluwalia's user avatar
4 votes
0 answers
424 views

Technique to remove factor structure from panel data

My preference is to use factor analysis rather than PCA. …
Ram Ahluwalia's user avatar
2 votes
0 answers
490 views

Approximate vs. Strict Factor model specification in R [closed]

Background: Generally, pooled time-series cross-sectional regressions utilize a strict factor model (i.e. require the covariance of residuals is zero). However, in time series such as security returns …
Ram Ahluwalia's user avatar
31 votes
7 answers
41k views

Testing for linear dependence among the columns of a matrix

I have a correlation matrix of security returns whose determinant is zero. (This is a bit surprising since the sample correlation matrix and the corresponding covariance matrix should theoretically be …
Ram Ahluwalia's user avatar