Common misunderstanding but the fed does not set rates on treasuries (bills, notes, etc) the primary instrument the government uses to finance its debts.
Those rates are set via auctions driven by the demand for safe haven returns on investments, particularly returns when equities are risky. As demand for treasuries (safety) goes up, the rates on those same treasuries go down.
The fed sets the interbank exchange rates, these influence treasury rates but are a very different thing.
i understand what you mean now. you are referring to the yield of treasury bonds, which, at least historically for <10 year tbills, do track the fed rate.