View source for Faq how do manually calculate the limits for scores

===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 (<code>modl</code>), the pc of interest (<code>pc</code>), and the % confidence limit level desired (<code>limitsvalue</code>):

 >> 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 <code>L = ...</code> line above with this:

 >> L = modl.detail.pcassq(pc,2);         %get PCR model eigenvalue

For PLS models, you must approximate <code>L</code> (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 <code>modl.detail.includ{1}</code> field to calculate <code>L</code> from only the included samples. 

'''Notes:''' 

To calculate limits for T2 and Q, see the [[Faq_how_do_I_calculate_my_own_T2_and_Q_limits| related FAQ.]]


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[[Category:FAQ]]