(A) Scatter plot between the threshold at 3 kHz (H3k) and the average of thresholds at 2 kHz and 4 kHz (H24k). (B) Distribution of the difference between H3k and H24k (weighted N = 39,357,497 × 2 ears).

<p>The scatter plot shows a statistically strong correlation between H3k and H24k (R = 0.92, p<0.0001). The predictive linear regression equation was <i>y</i> = –0.6821 + 1.0186<i>x</i> (<i>x</i> = H24k, <i>y</i> = H3k, p<0.0001, R² = 0.849). The difference between the H3k and H24k displays a distribution pattern that is similar to a normal distribution. M: million; dBHL: decibel hearing level.