Table 3 Variance of PRT with different velocities, volley types and illumination levels (s).

Source	SS	df	MS	F
S	.19710519	29	.00679673
Ball Velocity(A)	.04067969	1	.04067969	20.85*
S*A	.05657522	29	.00195087
Volley(B)	.00098983	1	.00098983	.38
S* B	.07569195	29	.00261007
Illumination(C)	.04471194	1	.04471194	24.28*
S* C	.05340871	29	.00184168
Ball Velocity* Volley (A* B)	.00003010	1	.00003010	.05
S*A* B	.01931962	29	.00066619
Ball Velocity* Illumination (A* C)	.00014137	1	.00014137	.41
S* A* C	.00996674	29	.00034368
Volley* Illumination(B* C)	.00002220	1	.00002220	.01
S* B* C	.04642442	29	.00160084
Ball Velocity* Volley* Illumination(A* B* C)	.00081181	1	.00081181	.83
S* A* B*C	.02834932	29	.00097756
Total	.57422813	239

* p < 0.05