Time Preference Is the Key Driver of Interest Rates
By popular thinking, whenever the central bank raises the growth rate of the money supply through the buying of financial assets such as Treasuries this pushes the prices of Treasuries higher and their yields lower. This is labeled as the monetary liquidity effect. This effect is inversely correlated with interest rates.
Furthermore, an increase in the money supply after a time lag strengthens economic activity and this pushes interest rates higher. Note that we have here a positive correlation between economic activity and interest rates.