Table 2.

Results of the Multivariate analysis of covariance (MANCOVA) applied to scales A, B and C of the Autism Diagnostic Interview-Revised (ADI-R) and the three univariate regressions separately relating each of the ADI-R scales to the covariates^a

	Multivariate analysis			Univariate analysis
Term	Pillai statistic	F(3,137) (P)	η2	ADI-R, scale A		ADI-R, scale B		ADI-R, scale C
				F(1,139) (P)	η2	F(1,139) (P)	η2	F(1,139) (P)	η2
Gender	0.07	3.4 (0.019)	0.07	5.7 (0.018)	0.04	9.0 (0.003)	0.06	4.9 (0.029)	0.03
Age	0.05	2.2 (0.090)	0.05	5.2 (0.024)	0.04	1.3 (0.253)	0.01	2.4 (0.126)	0.02
Verbal IQ	0.10	4.9 (0.003)	0.11	6.8 (0.01)	0.05	15.0 (<0.001)	0.10	2.1 (0.150)	0.01
Group	0.07	3.2 (0.025)	0.06	3.3 (0.070)	0.02	4.0 (0.046)	0.03	8.7 (0.004) 0.06

^a.Univariate analysis are all based on type III sums of squares. Partial eta-squared (η²) is a measure of effect size (small: 0.01; medium: 0.09; large: 0.25; based on the square of the Pearson correlation effect sizes from Cohen¹⁹). Multivariate η² = 1 – Λ^1/s where Λ = Wilks' lambda and s = minimum of the number of levels of the factor minus 1, or the number of dependent variables (here, s = 1 for continuous variables).²⁰