12.7 In a study of the influence of financial institutions on bond interest rates in Germany, quarterly data over a period of 12 years were analyzed. The postulated model was yi = b0 + b1x1i + b2x2i + ei where yi = change over the quarter in the bond interest rates x1i = change over the quarter in bond purchases by financial institutions x2i = change over the quarter in bond sales by financial institutions The estimated regression coefficients were as follows:

b1 = 0.046 b2 = -0.073 Interpret these estimates.