boltzmann {audiometry} | R Documentation |
s-shaped curve , originally used as discrimination function to draw the "normal" curves in the Freiburger Sprachtest before I could find the official norm values. Could still be usefull for someone seeking to add something like that to her plots be it as example or for simulation. The function is given as y = (exp(-4*(L-L_50))\*s_50)^-1 this is similar to a logistic regression result but with parameterization that is expecially usefull here:
boltzmann(L, L_50 = 18.4, s_50 = 0.08)
L |
sound pressure level for which the intelligibility is to be computed |
L_50 |
sound pressure level at 50% intelligibility |
s_50 |
intelligibility at L_50, happens to be 8% in Freiburger Zahlentest and 5% in Freiburger Einsilbertest (values taken from S. Hoth, Der Freiburger Sprachtest, HNO 2016, 64:540-48). |
predicted intelligibility
# Freiburger Einsilbertest has L_50 = 29.3 dB and s_50 at 5 %/dB.
# Compute the expected intelligibility at 20, 30 and 40 dB SPL
boltzmann(L = c(20, 30, 40), L_50 = 29.3, s_50 = .05)