pretty much like a strike zone, I try to identify when a fastball comes in or it might be a curve trying to brake my swing.

If a market is having negative returns as its z-value index is quite strong but getting weaker every day, then I know something is going on there, which is the case of gold = GC.

Or like corn which is getting some sponsorship when seeing positive return and a perseverant z-value: fastball coming in one of the corners willing to get hit by my swing.