Most called bingo numbers

Answer 1

If the set is manufactured and administered correctly, the odds are no higher for one number over others. That said, of course other factors can be involved if the set is old, or whatever.

You could sit out for a dozen games and keep track of the numbers. See if they seem non-random.

Answer 2

Over the long term, if any numbers are called with significantly higher frequency than any other numbers, then the game is not an honest game. The entire appeal of the game is based on the assumption of randomness. If that assumption is false, then it is a sucker's game, equivalent to loaded dice.