On 01/22/2013 11:12 AM, mary wrote:
Hi,
I have to construct an ellipse interval region on a PCAbiplot, I have my
parameters "a" and "b" and I would apply the formula:
draw.ellipse(x, y, a = , b = )
I have done a PCA on my data so I have my scores and loading for the first
and second component, but my answer is what I have to choose as X and Y into
the formula?
if "a" and "b" are scalars or vectors should be x and y scalars or vectors
too?
Hi Mary,
If this is draw.ellipse from the plotrix package, there should be an x
and y corresponding to each pair of a and b. I was unable to work out
which PCA biplot function you are using, so I am not sure whether the
plots are drawn in base graphics. If not, you might have some problems
with the x and y coordinates.
Jim
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