Table 6.

Results of a linear mixed model predicting changes in threshold on the three tasks as a function of age and single stimulus detection thresholds.

	Monaural			Binaural			Bilateral
	Value (%)	Lower limit (%)	Upper limit (%)	Value (%)	Lower	Upper	Value (%)	Lower limit (%)	Upper limit (%)
% INCREASE IN THRESHOLD FOR EVERY 10 YEARS OF AGE
Tone burst	31.3	18.2	45.8	15.1	−0.8	33.6	0.9	−11.3	14.8
Chirp	39.4	20.3	61.5	21.1	0.3	46.2	10.0	−0.1	21.1
Reversed chirp	28.3	5.8	55.7	17.6	−6.9	48.7	.	.	.
Noise chirp	21.6	−0.1	48.1	16.1	−5.7	43.0	.	.	.
% INCREASE IN THRESHOLD WITH 10% INCREASE IN SINGLE STIMULUS DETECTION THRESHOLD
Tone burst	5.4	−3.5	15.1	23.0	7.3	41.0	13.7	0.9	28.0
Chirp	10.2	−2.8	24.9	21.2	−1.3	48.9	9.4	−1.5	21.6
Reversed chirp	14.1	−7.0	39.9	21.0	−5.9	55.7	.	.	.
Noise chirp	27.9	3.9	57.5	29.2	3.3	61.6	.	.	.

For ease of comparison, only left ear values are shown for monaural tasks, but relationships were similar for the two ears. Seventeen different values were entered into the correlation matrix from which the values shown below are drawn (four tasks, two to four stimuli, left and right ears for the monaural tests, and age). Using the Bonferroni adjustment for multiple comparisons (p-value/number of comparisons) indicates that the p-value for significance used should be 0.00018, rather than 0.05. For the reversed chirp and noise chirp stimuli (n = 65), all correlations above 0.245 (6% of variance accounted for) are significant at the p < 0.05 level, while only those above 0.449 (20% of variance) are significant at the p < 0.00018 level. For the tone burst and chirp stimuli (n = 78), all correlations above 0.230 (5% of variance) are significant at the p < 0.05 level, while only those above 0.412 (17% of variance) are significant at the p < 0.00018 level. Significant correlations (p < 0.00018) are indicated in bold type. Marginally significant correlations (p < 0.05) are indicated by italics.