Table 5.

Analysis of variance of the model for total chlorophylls production

Source	Sum of squares	df	Mean square	F value	P value
x 1	6.45	1	6.45	1233.12	<0.05
x 2	9.77	1	9.77	1866.88	<0.05
x 3	0.13	1	0.13	26.49	<0.05
x 4	8.45	1	8.45	1614.72	<0.05
x 1 x 2	0.18	1	0.18	35.33	<0.05
x 1 x 3	0.01	1	0.01	2.10	0.28
x 1 x 4	0.20	1	0.20	39.55	<0.05
x 2 x 3	0.04	1	0.04	8.42	0.10
x 2 x 4	0.001	1	0.001	0.30	0.63
x 3 x 4	0.39	1	0.39	75.84	<0.05
x 1 2	0.54	1	0.54	103.81	<0.05
x 2 2	1.06	1	1.06	203.32	<0.05
x 3 2	1.93	1	1.93	370.45	<0.05
x 4 2	1.32	1	1.32	252.65	<0.05
Lack of fit	0.63	10	0.06	12.04	0.07
Pure error	0.01	2	0.005
Total	35.89	26

R² = 0 .98