Table 1.

Sources of variability and estimated variance components for three tutor behaviors over three semesters

Source of variability	Sum squared	Degrees of freedom	Mean squared	Estimated variance	% of Total variance
For expertise
Difference between tutors	113.70	761	0.1494	0.03745	50.0
Difference between semesters	0.68	2	0.3408	0.00040	0.5
Tutor-semester interaction and unidentified sources of variance in error	56.43	1522	0.0371	0.03708	49.5
For social congruence
Difference between tutors	187.75	761	0.2467	0.06755	60.5
Difference between semesters	0.22	2	0.1119	0.00009	0.1
Tutor-semester interaction and unidentified sources of variance in error	67.07	1522	0.0441	0.04406	39.4
For cognitive congruence
Difference between tutors	104.83	761	0.1377	0.03644	56.1
Difference between semesters	0.16	2	0.0788	0.00007	0.1
Tutor-semester interaction and unidentified sources of variance in error	43.27	1522	0.0284	0.02843	43.8