One way you can apply the training data statistics from one image to another is via a statistics file. To do this, open the ROIs and in the ROI tools, choose Options ->Calculate Covariance with Stats. Then select all of your ROIs and select the 'Stats' button which will plot the mean ROI spectra and calculate all of the necessary statistics for running a classifier. In the ROI statistics tool, go to File ->Save all ROI results to an ENVI statistics file. Now the training data statistics are in a file that can be used on another dataset. The only way to apply a pre-calculated statistics file in a classification is to use Endmember collection from Spectral ->Mapping Methods menu. Select the new file you want to classify. This brings up the Endmember Collection dialog. Select the algorithm you want to use under the Algorithm menu (notice there is no SVM or NN - these are not applicable for this method of classifying). Then go to Import ->From Stats File and open your ROI stats file you calculated previously. Once the spectra are imported, you can select Apply to continue through the classification.

Thank you very much, that is helpful. Cheers, Josh