2 things.
First.
For all this z-score/binomial distribution business to be valid you need to be absolutely sure that subject you explore is governed by bell curve as completely as roulette wheel is. I have no idea how that assumption can be made.
Second.
The chance that pattern you are looking at is already discovered, priced in and reflected in
odds, thus making your effort a complete waste of time, is overwhelming.
You can lose a lot of money in a process of confirming this empirically, or you can use common sense and very safely assume that finding an undiscovered long term profitable trend in a monstrous size market like NBA with millions upon millions of participants (some of whom are very sophisticated) looking at every aspect of it through the microscope is as likely as finding cold fusion.
Hope this helps.