6. Susan figured out a clever way to get 24 samples of monthly returns in just over one year instead of only 12 samples; she takes overlapping samples; that is, the first sample covers Jan. 1 to Feb. 1, and the second sample covers Jan. 15 to Feb. 15, and so forth. She figures that the error in her estimate of r, the mean monthly return, will be reduced by this method. Analyse Susan's idea. How does the variance of her estimate compare with that of the usual method of using 12 non-overlapping monthly returns