Use the MATLAB program from the previous problem and estimate the sample mean square error, $E_i=\mathrm{E}\left[e_i^2(n)\right]$ for each frame, $i$, where $\mathrm{E}[$. $]$ is the expectation operator.
a. Calculate the average MSE, $E_{\text {Avg }}=\frac{1}{N_f} \sum_{i=1}^{N_f} E_i$, where $N_f$ is the number of frames.
b. Repeat step (a) for a different number of sinusoids, e.g., $K=5,15,30$, 50 , and 60 . Plot $E_{\mathrm{Avg}}$ in $\mathrm{dB}$ across the number of sinusoids, $K$.
c. How does the MSE behave with respect to the number of sinusoids selected?