Quote from rmorse:
How can you say there is no relationship between delta and the probability of the option being in the money at expiration? The deeper ITM, the higher the delta. The more OTM, the lower the delta. Higher delta, higher probability, lower delta, lower probability._
Take the same priced stock, and lower the IV. You'll notice the ITM options now have a higher delta, than before, because there is now an even higher chance of staying ITM. (less of an expected chance of movement) with the lower IV, you will notice the OTM options have lower deltas, because of the lower expected movements, there is now a lower chance of being ITM at expiration.
Now, increase the IV. You'll see the opposite. There is more uncertainty. The ITM options delta goes down, the OTM options delta goes up._
One more. Increase time to expiration. The probability of anything occurring increases, so again, OTM option's delta increase, ITM decrease to compensate.
As i have said, The delta is also used as an estimated probability of the likely hood of being in the money._