Why the fuck do you care? All I know is that my stats were waaaay..... better then yours when I was 15. Dont lift cos you wonna impress someone dumbass, that's not what bodybuilding is about fool.
Way to be positive. I don't recall him asking what your stats were or how they compared. He just wants to know how he stacks up to the average person. It's not a crime and it doesn't mean he wants to impress someone. After all, he's going to be the only one who knows how he compares. Glad you thought your post through. And, whether you want to believe it or not, bodybuilding is indeed superficial by pretty much all accounts.
If I had to take a wild guess for the average stats of the average fifteen-year-old, it would probably be 150 ATG back squat, 150 deadlift, 135 bench. Those could be off by a mile, I really have no idea. I just figured that the average weight is probably somewhere around 150 and for the untrained individual, that might be average. Of course, this is difficult to test. You see, testing an untrained individual is impossible to do safely - you'd have to teach him proper form. However, the very act of learning proper form will most likely have increased his efficiency in the lifts.
Push yourself. Enjoy yourself. Be yourself.
Knowledge is power. Obsessed with functional strength. Journal