JMP Pro 11 Canonical plot

andreas_scherer

In JMP Pro 11 I am performing a Linear Discriminant analysis with two categories, each consisting of 26 observations. In the canonical plot, the 50% normal contour ellipsoids should frame 13 observations, but they only frame 5 and 6. Would anybody know why this would be the case?

 

 

 

 

Dan_Obermiller

From the JMP Help:

"The option Show Normal 50% Contours shows areas that contain roughly 50% of the points for that group if the assumptions are correct. Under linear discriminant analysis, they are all the same size and shape."

 

My additions: 

Assumptions: a normal distribution with common covariance for the two groups.

 

Remember that the ellipse is an ESTIMATE based on the model. It is not a guarantee of having 50% of the observations within the ellipse.