Table 1.

Participant characteristics.

Participant variable	ASD		FXS		t (df)	p	d	Variance ratio
	Mean	SD	Mean	SD
Chronological age	13.40	2.00	12.12	2.17	1.93 (35)	.061	0.61	1.17
MLU a	4.30	1.60	3.78	1.22	1.12 (35)	.272	0.37	0.58
ASD severity score b	7.22	2.24	7.00	1.67	0.34 (35)	.733	0.11	0.55
Nonverbal IQ c	71.22	19.88	48.89	8.09	4.43 (22)	.000	1.47	0.17
PPVT-4 standard score	74.39	16.70	63.68	12.57	2.21 (35)	.034	0.72	0.57
EVT-2 standard score	78.89	17.90	65.74	10.35	2.76 (35)	.009	0.90	0.33

Note. ASD = autism spectrum disorder; FXS = fragile X syndrome; MLU = mean length of utterance; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition; EVT-2 = Expressive Vocabulary Test–Second Edition.

^a Morpheme level MLU from conversation language samples.

^b Autism Diagnostic Observation Schedule (Lord et al., 1999, 2012).

^c Nonverbal IQ from brief IQ score from the Leiter International Performance Scale–Revised (Roid & Miller, 1997).