Fig. 3. Prediction probability (P^K) of weighted spectral median frequency (WSMF) based on development study A. Settings of the exponent  p (  x-axis ) are displayed between 0.4 and 2.4; settings of the cutoff frequencies  f ^high(  y-axis ) and  f ^low(  z -axis) are displayed between 25 Hz and 53 Hz and between 0.5 Hz and 15 Hz, respectively. In  A and  B , the P^Kvalues at the corresponding setting of  f ^low ,f ^high ,p are represented as  superposed colors , where the scaling of the P^Kvalues is indicated by  gradient bars . A maximal P^Kvalue of 0.824 results for WSMF with  f ^low= 8 Hz ,f ^high= 30 Hz, and  p = 0.4 that is situated near the frontal edge of the cube (  dark red area ). The cube in  B is interpolated, giving a continuous approximation of the discrete settings to obtain a better presentation. The cube in  C shows only values of P^K≥ 0.82, which are represented by  black dots. They occur as two “clusters,” one as “high-frequency cluster” with  f ^high≥ 40 Hz and one as “low-frequency cluster” with  f ^high≤ 30 Hz.