. Author manuscript; available in PMC: 2009 May 1.

Published in final edited form as: Am J Speech Lang Pathol. 2008 May;17(2):121–138. doi: 10.1044/1058-0360(2008/013)

Table 7.

Results of linear and quadratic regression analyses for PLS and PPVT at chronologic Test Age 4.5 years

		Step 1 – Linear Regression				Step 2 – Quadratic Regression
Test/Subscale	Parameter	Regression Coefficient (β)	Standard Error	Semi-Partial r²	Step Increment in R²	Regression Coefficient (β)	Standard Error	Semi-Partial r²	Step Increment in R²
PLS Auditory Comprehension					.337				.016
	Intercept	152.868	12.495			176.297	21.703
	Pre-CI Aided	-.574^***	.136	.161		-.563^***	.136	.154
	Age at CI	-1.456^***	.257	.292		-3.700^*	1.723	.042
	(Age at CI)²	-	-			.047	.035	.016
PLS Expressive Communication					.361				.050
	Intercept	151.082	13.812			198.187	23.314
	Pre-CI Aided	-.521^***	.151	.104		-.498^***	.146	.095
	Age at CI	-1.794^***	.284	.349		-6.305^***	1.851	.095
	(Age at CI)²	-	-			.094^*	.038	.050
PPVT					.363				.002
	Intercept	158.664	12.406			167.900	21.740
	Pre-CI Aided	-.607^***	.135	.178		-.602^***	.136	.174
	Age at CI	-1.511^***	.254	.312		-2.402	1.735	.017
	(Age at CI)²	-	-			.019	.036	.002

^***

p ≤ .001

^**

p ≤ .01

p ≤ .05

Note: Squared semi-partial correlations can sum to greater than the squared multiple correlation under conditions of suppression. This occurs when the effect of a predictor is suppressed by another predictor and is only revealed when the other predictor is partialled. CI = Cochlear Implant, RS = Raw Score