Table 4. Results of the Tests of the Fixed Effects for Rotor Performance, Verbal Fluency, Grammatical Complexity, and Linguistic Content Measures.

	Tests of Fixed Effects
	Task Difficulty (2, 194)	Age Group (1, 195)	Task Difficulty x Age Group (2, 194)
Performance
Time on Task	2736.57**	<1.0	2.28
Error	6006.49**	<1.0	3.08
Fluency
Speech rate	341.70 **	60.73**	36.66**
% with Fillers	70.77**	282.14**	61.37**
% Grammatical	11.81**	38.82**	54.75**
Mean Length Utterance	390.55**	43.67**	100.54**
Complexity
Developmental Level	250.52**	21.26**	17.45**
Grammatical Index	2169.48**	28.10**	32.34**
Content
Propositional Density	7908.61**	339.36**	1313.81**
Coherence Index	399.96**	11.18**	23.08**
Type Token Ratio	5.01*	11.42**	14.60**

^*p < .05

^**p < .01