Unobservable

variables like player ability (shoot accuracy, speed, strength and

resistance) is negatively correlated with salary of the player and are also positively correlated with experience and points per game.

Unobservable variables like player ability (shoot accuracy, speed, strength and resistance) is positively correlated with salary of the player and are also positively correlated with experience and points per game.

All the necessary variables have already been accounted for in the model so there are no unobservable variables that can bias the estimates.