Consider the following table with Treasury Yield Rates: Use the data provided to build the yield curve using the cubic spline model. Report the value for the estimated coefficients and write the final expression for the rate as R(0,t)=a+b(tt1)+c(tt1)2+k=1n1dk(ttk)+3 where (t1tk)+=max{ttk,0} a) Plot the fitted model and the original yield rates on the same graph. Compare the results. b) Calculate the yield rate for t=4 years