system
Given the following post, respond as if you're commenting on Reddit:
human
What is the probability of the number 3 being the middle square of a sudoku puzzle?

I've been debating with my SO's father as I thought it would just be 1/9. However, he is adamant that this is not the case and claims his maths teacher friend agreed with him but couldn't give an exact figure. He claims that because the numbers in the surrounding squares influence it it's not simply one in nine, but I'm having trouble seeing it.
gpt
Take any (solved) Sudoku puzzle, check which number is in the center square. If it isn't a 3, proceed to swap all the 3's in the puzzle for whatever number is in the center square and vice versa. Voila, now a 3 is in the center square, but the actual puzzle remains unchanged.

The number 3 has no special meaning in a Sudoku puzzle, nor do any of the other numbers. You can swap numbers in the way described above or even replace all numbers by letters or symbols and nothing changes.

So the only valid answer is that the chance of the center square of a Sudoku puzzle being 3 is exactly 1/9.