I did PCA for some variables which were Likert scaled questions (1-5). After predicting, I get negative for some of the values. Is there something wrong? Do I take absolute values of the predicted variable ?
Note: The Eigen values were positive
The values in the new variable (after predicting) is given as attachments
The stata output are as follows:
pca v1 v2 v3 v4
Principal components/correlation Number of obs = 302
Number of comp. = 4
Trace = 4
Rotation: (unrotated = principal) Rho = 1.0000
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Component | Eigenvalue Difference Proportion Cumulative
-------------+-----------------------------------------------------------------------------------------------
Comp1 | 1.50368 .51615 0.3759 0.3759
Comp2 | .987535 .16249 0.2469 0.6228
Comp3 | .825045 .141311 0.2063 0.8291
Comp4 | .683735 . 0.1709 1.0000
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Principal components (eigenvectors)
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Variable | Comp1 Comp2 Comp3 Comp4 | Unexplained
-------------+----------------------------------------+------------------------------------------------
v1 | 0.6017 0.0522 -0.3627 -0.7097 | 0
v2 | 0.5426 -0.4256 -0.3741 0.6200 | 0
v3 | 0.5034 -0.1359 0.8531 -0.0192 | 0
v4 | 0.3001 0.8931 -0.0273 0.3340 | 0
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