jobs in non profit organization Before that, what is the nature of the enterprise itself is an issue that has been ignored by traditional microeconomic theory. In the traditional microeconomic theory, is the manufacturer's production process as a "black box", namely enterprise is abstracted into a from input to output a "black box" of the pursuit of profit maximization. Keynes argued that savings and investment were two interdependent variables, not two independent variables. Alpesh Paleja, chief economist at CBI, said: "although sales have grown in the past few months, the basic trading conditions for retailers remain difficult. We expect that the pressures on households to actually pay will continue for a while, so retailers still face challenges. " Interest rate, in the form of expression, refers to the ratio of the amount of interest to the total amount of borrowed capital in a certain period of time.  the interest rate is the interest level per unit time of the unit currency, indicating the interest rate. Economists have been looking for a theory that can fully explain the structure and change of interest rates. Interest rates are usually controlled by the central bank of the country and administered by the federal reserve board in the United States. Today, interest rates are one of the important tools for macroeconomic regulation.