I'd like to know too, I know that they show which one's stronger than the other but I don't know where they came from. Is it from the Pokemon at level 50/100?
Lets say a Sceptile, it has 65 for Defense, 105 for Special Attack and 120 for Speed. So, when it levels up, its Defense gets the lowest boost and Speed gets the highest boost. If it doesn't receive any IV or EV during its training, it will reach the base stat when it grows to Level 50. I once focused on my Sceptile's Speed and when it's Level 36, it's Speed is already 114. When it is Level 50, its Speed is 152.