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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Anti-Spam Code: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by gotophysics[/i] [br]Hello @all, I'm a student and work with Origin 9 Pro. At the Moment I try to distinguish different NIR-spectra with a PCA. Therefore I have 4 samples (objects) with their belonging frequency-dependind absorptionvalues (234 variables). My Problem is that I can't perform a PCA. I put the objects (sample names) in the raws of column A(X) and the absorption values for each wavenumber in the colums B(Y) up to C234(Y): A(X) B(Y) C1(Y) C2(Y) C3(Y) C4(Y) ... sample1 --> 236 Absorption values (spectra of sample 1) sample2 --> 236 Absorption values sample3 --> 236 Absorption values sample4 --> 236 Absorption values So each row contains one spectra as each column contains the absorption values of one frequency of 4 different samples. Now I'd like to perform the PCA, but I get the error message that the numbers von objects is lower than the number of variabels, so a PCA can not be performed. But if I Change raws and colums I have a different problem. The PCA works, but the results are unphysical. The PCA assumes 4 Absorption values, belonging to one wavenumber BUT to 4 different samplespectra. I'd like to reduce the whole spectra of one sample to the principal components. Can you give me some advises how to proceed? Thank you very much. [/quote]   Check here to include your profile signature. Check here to subscribe to this topic.