First off, thanks for providing that spreadsheet. I've used it a bunch since you posted it. But that wasn't the question at hand.

I did use statistically significant wrong, my apologies. What I was trying to say is:
  • What's the value of an increase in 1 weighted stat point? If we're talking gear sets in the 600+ point range, is 1 point really an effect of 1/600th?
  • At what stat point increase does an investment in time/gil/tombes show meaningful results? I realize this is subjective, but I'm sure no one would spend 1 million gil for a .5 increase if that doesn't make any real difference to your DPS. Should one look for a boost of x% to consider something worthwhile?

Again, I realize more is always better, but when balancing that against a cost, it is not always smart. Just trying to wrap my head around when stats will make a real difference versus being an ineffective upgrade.