**2.6 The fluctuations around the mean for bimodal square waves**

An advantage of using random square waves as shown in Figure 2 is that they generate only two fluctuation amplitudes for each variable, which are then used to calculate the wished statistical quantities. Of course, the functions defined in sections 2.3 through 2.5 (partition, reduction and superposition functions) are also used, and they must "adjust" the statistical quantities to adequate values. From equations (8), (10), and (11), the two instantaneous scalar fluctuations are then given by equations (14) and (15)

$$f\_1 = \left(F\_p - P - \overline{F}\right) = (1 - n)\left(F\_p - F\_n\right)\left(1 - \alpha\_f\right) \quad \text{(positive)}\tag{14}$$

$$\mathbb{E}\left(f\_2 = \left(F\_n + N - \overline{F}\right) = -n\left(F\_p - F\_n\right)\left(1 - \alpha\_f\right) \quad \text{(negative)}\right) \tag{15}$$
