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Table 3 ANOVA test performed on the second-order polynomial model used to discriminate between the significant linear (L) and quadratic (Q) effects of the investigated variables, as well as their interactions, for the investigated system and response (biohydrogen production)

From: Revealing the factors influencing a fermentative biohydrogen production process using industrial wastewater as fermentation substrate

 

Sum of squares (SS)

Degree of freedom

Mean square

F-value

P-value

X1-L

270.935*

1*

270.935*

11.63704*

0.001725*

X1-Q

260.138*

1*

260.138*

11.17333*

0.002075*

X2-L

1314.436*

1*

1314.436*

56.45696*

0.000000*

X2-Q

185.342*

1*

185.342*

7.96069*

0.008033*

X3-L

61.992

1

61.992

2.66265

0.112237

X3-Q

0.236

1

0.236

0.01013

0.920420

X1X2

140.261*

1*

140.261*

6.02441*

0.019553*

X1X3

15.980

1

15.980

0.68634

0.413363

X2X3

0.291

1

0.291

0.01250

0.911647

Lack of fit

273.054

5

54.611

2.34561

0.062915

Pure error

768.309

33

23.282

-

-

Total SS

3290.973

47

-

-

-

  1. *Values considered statistically significant.