Table 1.

Primary demographic and behavioral variables at person- and assessment-levels

	FXS					Control
Model	n	Mean	SD	Min	Max	n	Mean	SD	Min	Max
Person-Level Variables
n Assessments	46	2.39	0.49	2	3	33	2	0	2	2
Baseline Age (months)	46	26.86	9.15	10.82	37.97	33	27.50	8.82	12.07	38.10
Outcome Age (months)	46	59.02	8.24	40.51	69.77	32	41.68	9.02	24.49	57.57
Outcome Mental Age (months)	46	31.96	11.70	13.75	67.25	33	46.53	10.08	22	66
Outcome Cognitive SS	46	54.65	11.66	47	99	33	111.06	15.46	82	141
Autistic Symptoms	46	27.41	6.54	16.5	40	33	15.18	0.64	15	18.5
Anxiety Raw	46	4.07	2.78	0	13	32	1.97	1.89	0	6
Anxiety T	46	55.63	6.92	50	81	32	51.66	2.89	50	60
Withdrawal Raw	46	4.30	2.56	0	12	32	0.72	1.20	0	4
Withdrawal T	46	63.96	8.51	50	88	32	51.84	3.90	50	63
Assessment-Level Variables
Chronological Age (months)	110	38.85	13.57	10.82	59.93	66	35.08	11.59	12.07	57.83
Facial Fear	108	0.06	0.12	0.00	0.67	65	0.09	0.13	0.00	0.60
Distress Vocalizations	109	0.22	0.35	0.00	1.98	66	0.15	0.47	0.00	2.76
Escape Behaviors	110	1.10	0.61	0.00	2.63	66	1.05	0.48	0.07	1.87

Note: Person-level variables refer to demographic and behavioral features collected during one observation (e.g. outcome anxiety) or are summarized as one variable (e.g. number assessments), whereas assessment-level variables were collected at each time point (e.g. facial fear at age 10 months). Thus, each participant contributed one observation per person-level variable and multiple observations per assessment-level variable.