They have a price correlation indeed but inversely, so when bitcoin price goes up, ltc and other altcoins goes down. Maybe only a few exceptions perhaps (the peaked last Dec 2017), but overall the movement is always on opposite direction.

Maybe you going to ask why? Its because investors have this tendency of just moving the funds around. They follow the money, so when we see that there is a bitcoin rally, investors shifts their funds from altcoins to bitcoin and vice versa. I hope you got the point.