FAQ  Frequently Asked Questions
Issue:

How do I manually calculate the limits for scores?
Possible Solutions:

Individual scores limits can be calculated using the code below, given a PCA model (modl), the pc of interest (pc), and the % confidence limit level desired (limitsvalue):
pc = 2; %which PC to calculate limit for limitsvalue = 95; % confidence level (in %) L = modl.detail.ssq(pc,2); %get eigenvalue m = length(modl.detail.includ{1,1}); %get number of samples scorelimit = sqrt(L * tsqlim(m,1,limitsvalue));
To calculate scores limits for PCR models, the above must be slightly modified because the eigenvalues are stored in a different field. Replace the "L = ..." line above with this:
L = modl.detail.pcassq(pc,2); %get PCR model eigenvalue
For PLS models, you must approximate L (the eigenvalue) from the RMSE of the calibration data scores:
L = rmse(modl.loads{1,1}(:,pc)).^2; %estimate PLS model eigenvalue
This code assumes that no samples were excluded in the model. If any samples were excluded, use the
modl.detail.includ{1}
field to calculate L from only the included samples.
Notes:
 To calculate limits for T^{2} and Q, see the related FAQ.
 Note that in some older versions of PLS_Toolbox, scores were calculated slightly differently than this method. For more information see this related FAQ.
Still having problems? Check our documentation Wiki or try writing our helpdesk at helpdesk@eigenvector.com