. Author manuscript; available in PMC: 2012 Feb 21.

Published in final edited form as: Am J Intellect Dev Disabil. 2011 Mar;116(2):142–152. doi: 10.1352/1944-7558-116.2.142

TABLE 4.

Summary of Two-Part Random-Effects Models (Parameter Estimates and Standard Errors) Assessing the Probability of Awakening at Night (WASO Occurrence) and the Intensity of Awakening (WASO Number and Duration)

Model Term^a	WASO Number	WASO Duration
WASO occurrence (logistic)
AUT–TYP difference	−0.50 (0.21)^*	−0.49 (0.21)^*
DD–TYP difference	0.20 (0.23)	0.17 (0.22)
AUT–DD difference	−0.70 (0.23)^**	−0.64 (0.22)^**
Time	−0.09 (0.02)^***	−0.09 (0.02)^***
Variance of random effects	1.16 (0.20)^**	1.03 (0.18)^**
WASO intensity (lognormal scale)
AUT–TYP difference	−0.21 (0.07)^**	−0.16 (0.09)
DD–TYP difference	0.06 (0.07)	0.24 (0.10)^*
AUT–DD difference	−0.27 (0.07)^***	−0.39 (0.10)^***
Time	−0.01 (0.00)^**	−0.02 (0.01)^*
Variance of random effects	0.14 (0.02)^***	0.23 (0.03)^***
Residual variance	0.42 (0.01)^***	0.92 (0.03)^***
Covariance	0.36 (0.05)^***	0.38 (0.06)^***

Note. Analyses used a two-part logistic-log normal-normal mixed-effect model with correlated random effects. WASO = wake after sleep onset; AUT = autism; TYP = typically developing; DD = developmental delay without AUT.

Models were adjusted for demographic characteristics (ethnicity, mother’s age, marital status, and education).

p < :05.

^**

p < :01.

^***

p < :001.