Statistical distribution of normal hearing thresholds under free-field listening conditions

Abstract

The statistical distribution of normal hearing thresholds for pure tones of frontal incidence under binaural, free-field listening conditions was estimated as a function of frequency. First, the form of threshold distribution was investigated with threshold measurement data of the present study and those of other studies. Analytical results indicate that the threshold distribution has a form of normal distribution for the frequency range from 25 Hz to 16 kHz. Second, under the assumption of normality, standard deviations of thresholds were calculated for the frequency range from 25 Hz to 18 kHz by combining available threshold data of different studies. A supplementary experiment showed that thresholds at frequencies above 16 kHz were measurable with high reliability. These results illustrate the profile of our auditory sensitivity more accurately because they account for individual differences.

How large is the individual difference in hearing sensitivity?: Establishment of ISO 28961 on the statistical distribution of hearing thresholds of otologically normal young persons

“…This figure plots the skewness that the authors derived from two sets of threshold data for 89 individuals [4,19]. It is observed that the skewness deviates from zero at frequencies of 10,000 Hz and above.…”

“…Form of Hearing Threshold Distribution 2.3.1. At frequencies lower than 10,000 Hz [4] Statistical processing of the data and description of the results become easier if the dispersion of individual data can be approximated using a normal distribution (see Sect. 2.4).…”

“…First, threshold data of 89 individuals that the authors collected [4,19] were used for statistical analyses. The results of a test for the goodness of fit to a normal distribution showed that deviation of the data from a normal distribution was not statistically significant at frequencies of 1,000 Hz to 16,000 Hz.…”

“…Second, threshold distributions of four datasets, two measured by the authors [4,19] and the other two referred from the literature [13,14], were examined in terms of their asymmetry and peakedness. These two measures respectively resembled skewness and kurtosis, but they differed in that they were calculable using the 25th and 75th percentiles reported in the literature.…”

“…Results of the research on which ISO 28961 is based have been published in four journal papers [4][5][6][7]. The threshold data that were used and the procedures for estimating the form of threshold distribution are described there.…”