Table 3.

Sequential model sum of squares.

Source	Sum of squares	Degree of freedom	Mean square	F-value	Prob. > F
Mean	2.57	1	2.57
Linear	0.05	3	1.63E − 02	24.51	<0.0001
2FI	4.16E − 04	3	1.39E − 04	0.18	0.91
Quadratic	9.11E − 03	3	3.04E − 03	27.48	<0.0001	Suggested
Cubic	6.76E − 04	4	1.69E − 04	2.36	0.17	Biased
Residual	4.29E − 04	6	7.15E − 05
Total	2.63	20	0.13