Table 2: Whole-cohort testing characteristics.

Bolded entries indicate p<0.05 for significant group difference below testing norms. T-scores are normed against typical validation groups with mean scores of 50 and a standard deviation of 10. Standard scores are normed against typical validation groups with mean scores of 100 and a standard deviation of 15.

	Estimate	95% Confidence interval	p-value
Mullens RL T-score	49.0	[45.0,52.5]	0.57
Mullens EL T-score	44.5	[41.0,48.0]	0.0023
Mullens VR T-score	42.5	[38.5,46.5]	0.0015
Mullens FM T-score	42.0	[38.5, 45.0]	0.000062
Mullens ELC standard score	90.5	[85.0,96.0]	0.0016
M-B Production percentile	27.5	[20.0,40.0]	0.00087
M-B M3L percentile	35.0	[25.0,47.5]	0.016
	Estimated group difference	95% Confidence interval	p-value
Mullens RLt-VRt	+6.0	[1.0,11.0]	0.018
Mullens RLt-ELCt	+5.0	[0.67,10.0]	0.037
Mullens RLt-ELt	+4.0	[0,9.0]	0.083

Abbreviations: ELt: Mullen expressive language T-score; RLt: Mullen receptive language T-score; ELC: Mullen Early Learning Composite; M-B: MacArthur-Bates Communicative Development Inventories; M3L: MacArthur-Bates mean of 3 longest utterance percentile