Table 5. Analysis of variance for the experimental results of the central composite design (CCD).



Source

DF

Sum of Squares

Mean Square

F Value

Prob > F

X2 a

1

4565.25

4565.25

15.58

0.0056**

X4

1

33.00

33.00

0.11

0.7470

X22

1

15629.14

15629.14

53.34

0.0002**

X42

1

36511.52

36511.52

124.61

< 0.0001**

X2X4

1

1148.87

1148.87

3.92

0.0882*

Model

5

52450.67

10490.13

35.80

< 0.0001**

Error

4

492.84

123.21

Total

12

54501.64

R2 = 0.9624

Adj-R2 = 0.9355

R = 0.9810

a The symbols were the same those in Table 1.
* Statistically significant at 90% of probability level.
** Statistically significant at 99% of probability level.


Supported by UNESCO / MIRCEN network