Dear all I would greaty appreaciate any help with the following. Can Pearson correlation coefficients from data on different range or scale be compared??.For example, if I compute the (r) value from a pair of intensity ratio datasets spanning the range -10 to +10, can I compare it with an the (r) value from another pair of intensity ratio datasets spanning a different range say -5 to +5. Similarily, can I compare the (r) value from correlating a pair of intensity ratio datasets with that from correlating a pair of absolute intensity datasets (where the scale of the data is different). The question that I would want to address from such comparison is whether the ratios covary better than the raw intensities. Please let me know if this is not clear enough... Many thanks.