Fig. 4. Prediction probability (P^K) of weighted spectral median frequency (WSMF) based on development study A at three fixed levels of the low cutoff frequency  f ^lowwith variable settings of the exponent  p (  x-axis ) between 0.4 and 2.4 and high cutoff frequency  f ^high(  y-axis ) between 25 Hz and 53 Hz. In  A , f ^low= 0.5 Hz; in  B, f ^low= 8 Hz; and in  C, f ^low= 13 Hz. The resulting P^Kvalues of WSMF with the corresponding settings of  p and  f ^highare represented as  superposed colors , where the scaling of the P^Kvalues is indicated by  gradient bars . P^Kvalues are interpolated.  A contains the configuration of median frequency (MF) with  f ^low= 0.5 Hz,  f ^high= 30 Hz,  p = 2,  r = 0.5 leading to a P^Kof 0.55 (all P^Kvalues smaller than 0.66 are represented by  dark blue ). B contains the configurations of WSMF that provide maximal P^Kvalues in the range of 0.82 within both “clusters” shown in  figure 3C (  dark red areas ):  f ^low= 8 Hz,  f ^high= 49 Hz,  p = 1,  r = 0.5 (denoted by WSMF^8–49) and  f ^low= 8 Hz,  f ^high= 30 Hz , p = 0.4 , r = 0.5 (denoted by WSMF^8–30).