I’ve seen reference that people tend to bias towards odd numbers for “random” numbers. I wouldn’t be surprised if we consider prime numbers to “be even more randomer”.
> I’ve seen reference that people tend to bias towards odd numbers for “random” numbers.
I can see the logic behind that, but for the trick in question it’s not like they have a choice (emphasis added):
> Ask your friend to quickly think of a two-digit number between 1 and 100, both digits odd and both digits different from each other.
One thing they don’t mention on the page is that after all the constraints, only a fifth of the original hundred are valid choices: 13, 15, 17, 19, 31, 35, 37, 39, 51, 53, 57, 59, 71, 73, 75, 79, 91, 93, 95, 97. So while on the surface it may seem like you’re guessing one number out of a hundred, you’re guessing one out of twenty.
