No idea what any of that means but it sounds bad
It's just an extremely simple math thing -- like, beginning algebra -- that absolutely everyone is supposed to know how to do before starting the first term of Principles.
It's now the second term.
Also, being that far in they should know how to look it up. I literally forgot what linear regression was, knew I should know it, and simply used the internet to get me to the wikipedia article on how to do linear regression.