Is there a way to plot original set of data onto biplot?

I want to plot all of my original data as a scatter plot onto the biplot created by PCA.

Answer 1

[Peter Perkins]

Michelle, the whole point of PCA is to create a new coordinate system. Plotting the original data in that coordinate system doesn't make sense. If you've done PCA, you must have the scores for your original data -- the scores are the original data transformed into the new coordinate system. Use BIPLOT to plot those - there's an optional parameter to do that.

Hope this helps.

[Michelle]

Thank you!

[dpb]

...the whole point of PCA is to create a new coordinate system. ...

Good point, Peter... :)

Answer 2

[dpb]

biplot(...
hold on
scatter(gca,x,y);

should get you started.

[Michelle]

Thank you!

[dpb]

Other than Peter's obvious, of course... :)