Box-and-whisker plot (left) for the mean difference and limit of agreement (right) of difference between the threshold at 3 kHz (H3k) and the average of thresholds at 2 kHz and 4 kHz (H24k) against the threshold groups. (A) 2 kHz; (B) 3 kHz; (C) 4 kHz; and (D) four-tone (0.5, 1, 2, and 3 kHz) average (weighted N = 39,357,497 × 2 ears).

<p>These graphs show that the degree of hearing thresholds at the three frequencies and at the four-tone average did not affect the distribution of the difference between H3k and H24k. However, the upper and lower limits of agreement are roughly greater than 10 dBHL and less than –10 dBHL, respectively. ※Threshold groups are divided as follows: normal (<26 dBHL), mild (26–40 dBHL), moderate (41–55 dBHL), moderately severe (56–70 dBHL), severe (71–90 dBHL), and profound (>90 dBHL); dBHL: decibel hearing level.