Yes and No. The mediator has no coercive power over the parties. All have different styles: some are more evaluative of the parties positions, preferring to actively guide the parties to a settlement; others are more passive, serving only as facilitators for joint problem solving and dialogue. But no mediator can force the parties to take a certain position or accept a proposed settlement.
However, any agreement reached by the parties during the mediation session must be memorialized in writing before leaving the session. Such agreements are binding on the parties. They are as legally enforceable as any other contract the parties may freely enter in to. In this respect, the mediation is binding.