Naive analytical estimates of the contribution to the variance as a function of multipole and frequency, as given in Eq. (4). We assume the same bin sizes as in Fig. 3. The different lines are the contribution to the analytical error from: the signal only, (orange); noise only, (dark blue); and the mixed signal and noise terms, (orange) and (red). The total contribution is the solid black line, and the theory spectrum, , is the dashed black line.