There is an obvious problem in trying to cross-correlate price change and volume: price change can be positive or negative, but volume is only positive. Actually volume is only REPORTED positive. It can be either positive or negative, a fact that never seems to disturb those who talk about the relationship of volume to price. But all volume in a bar is aggregated. In fact positive volume is very close to negative volume, at least for NQ, so this is not a big issue. (Believe me, if it were, and it had any value, I wouldn't say anything about it.) So the right way to cross correlate price change with volume is to make all price changes positive by taking the absolute value. As Infolode hinted, this amounts to frequency doubling because it is full-wave rectification. The scattergram for rectified price change versus volume is attached. Is there a relationship there? If so, it is pretty weak. We'll see when we do the cross-correlation that the correlation coefficient is so low as to make an hypothesis of causality between price change and volume suspect.
