[gaming_mouse]

I have a pocket pair with no cards on the board yet. My odds of improving my hand are 4:1 by the river.

You're thinking about this wrong. It is almost NEVER correct to see the river with a low pocket pair whose only value comes from the possibility of spiking a set, assuming you have missed your set on the flop.

You are about a 7.5 : 1 dog to spike your set on the flop. However, that does not mean you need 7.5 : 1 pot odds preflop. In an agressive game, even if only 4 or 5 opponents see the flop (giving only 4:1 pot odds), you will have correct implied odds, because you can count on lots of action postflop when you spike your set.

Nonetheless, your strategy is ALMOST ALWAYS to give it up if you miss on the flop. The reason is that you have only 2 outs. So your chance of hitting your set on the turn is only 2/47; same goes for the river. You will almost NEVER have correct pot (or implied) odds to make these calls correct.

HTH,
gm