Table 1.

Characteristics of Study 1 replication sample

Mean (SD) Range	Low-risk n = 3309	High-risk n = 484	Total n = 3793	F
Male	1,649	354	2,003	N/A
Female	1,621	122	1,743	N/A
Sex not reported	39	8	47	N/A
Age in months at screening	20.53 (3.06)	24.25 (3.60)	21.01 (3.37)	576.56**
	16.00–30.85	16.23–30.62	16.00–30.85
M-CHAT total items failed	.85 (1.35)	4.21 (4.98)	1.28 (2.44)	990.53**
	0–19	0–19	0–19
M-CHAT critical items failed	.10 (.45)	1.44 (1.95)	.27 (.92)	1168.24**
	0–6	0–6	0–6
Age in months at telephone interview*	22.71 (3.83)	25.63 (3.85)	24.09 (4.05)	53.88**
	17.51–36.01	16.62–34.07	16.62–36.01
M-CHAT total items failed for screen positive cases*	4.50 (2.91)	8.84 (4.44)	6.74 (4.35)	130.21**
	2–19	2–19	2–19
M-CHAT critical items failed for screen positive cases*	1.04 (1.33)	3.19 (1.83)	2.15 (1.93)	177.42**
	2–6	0–6	0–6
Telephone interview total items failed*	1.51 (3.11)	5.26 (4.92)	3.41 (4.53)	82.12**
	0–19	0–18	0–19
Telephone interview critical items failed*	.52 (1.21)	1.99 (1.95)	1.26 (1.79)	80.82**
	0–6	0–6	0–6

^*n for telephone interview is 189 low-risk, 196 high-risk, and 385 total

^**p < .01