Steve is exploring the relationship between the price of a house, its number of rooms, and its distance from the subway. When Steve regresses house prices on the number of rooms, he finds a positive coefficient. Steve then regresses house prices on both the number of rooms and the distance to the subway. He gets a positive coefficient on both variables, though the coefficient on rooms is smaller than before. What does he know about the correlation of rooms and distance?
A. They are positively correlated
B. They are negatively correlated
C. We cannot infer the direction of their correlation
D. They are not correlated
Answer: A. They are positively correlated