Variation explained by the first principal component

[RK2509]

Hi Tom,

I performed principal component analysis for a set of 72 food prices. I estimated the first two principal components. But I want to know the percentage of variation explained by the first two principal components. Is there any specific command for that in RATS ?

Many Many Thanks

[TomDoan]

Use @PRINFACTORS.

[RK2509]

So, if I get something like this using prinfactors

Sample Output:

Principal Components Analysis
Eigenvalue 2.607649 1.071584 0.568616 0.451315 0.300836
Proportion 0.521530 0.214317 0.113723 0.090263 0.060167
Cumulative 0.521530 0.735847 0.849570 0.939833 1.000000
Eigenvector -0.427633 -0.341113 0.837079 0.001756 0.008203
-0.459893 -0.356458 -0.380141 -0.704282 0.144622
-0.451115 -0.385464 -0.389227 0.704231 0.021777
-0.478567 0.469467 -0.045824 -0.052077 -0.738757
-0.416049 0.622573 0.034557 0.073012 0.657861

Does the row 'proportion' explain the percentage of variation corresponding to each eigenvalue? So here this would mean the first principal component explains 52 percent of the variation? what does the row "cumulative" explain?

Thank you so much.

[TomDoan]

Proportion is the proportion attributable to that component alone. Cumulative is the sum of all components from 1 to that components.

[RK2509]

Many Many Thanks.