In the game, there is a chance for a particular stat to appear, such as attack, defense, etc. These are presented in the game manual on page 300. For example, at level 21, a mage has: 2 attacks, 3 defenses, 8 spells, and 12 knowledge points. This has all been invented a long time ago. The fact that these are chances means that they may differ slightly from the stated values; this is probability theory. So, if you understand all this, you won't be surprised by anything.
I have known this for a long time (I'm talking about what is written in the manual). I am saying that this percentage does not reflect the actual chance. Well, maybe at level 1000, or even at level 40, the percentage correctly reflects the distribution (which is also not true), but in the early game, it rarely corresponds.