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Table 2 Analysis of variance (ANOVA) for the model

From: Optimization of phenolics and flavonoids extraction conditions of Curcuma Zedoaria leaves using response surface methodology

Sources

Sum of squares

Degree of freedom

Mean squares

F-value

p-value

Phenolic content (mg/g GAE)

 Model

1191.21

9

132.36

1662.76

< 0.0001

 X 1 -temperature

450.69

1

450.69

5661.84

< 0.0001

 X 2 -Time

56.30

1

56.30

707.27

< 0.0001

 X 3 -solvent ratio

229.32

1

229.32

2880.92

< 0.0001

 X 1 X 2

135.30

1

135.30

1699.75

< 0.0001

 X 1 X 3

20.87

1

20.87

262.13

< 0.0001

 X 2 X 3

61.38

1

61.38

771.14

< 0.0001

 X 2 1

25.87

1

25.87

325.02

< 0.0001

 X 2 2

20.46

1

20.46

257.06

< 0.0001

 X 2 3

181.23

1

181.23

2276.79

< 0.0001

 Residual

0.80

10

0.080

  

 Lack of fit

0.63

5

0.13

3.74

0.0870

 Pure error

0.17

5

0.034

  

Cor total

1192.01

19

   

R2 = 0.9993

Adj. R2 = 0.9987

CV% = 0.24

Flavonoid content (mg QE/g of extract)

 Model

0.22

9

0.024

229.66

< 0.0001

 X 1 -temperature

0.002

1

0.002

21.86

0.0009

 X 2 -Time

0.003

1

0.003

31.89

0.0002

 X 3 -solvent ratio

0.11

1

0.11

1065.88

< 0.0001

 X 1 X 2

0.0006

1

0.0006

5.82

0.0365

 X 1 X 3

0.033

1

0.033

308.93

< 0.0001

 X 2 X 3

0.012

1

0.012

114.14

< 0.0001

 X 2 1

0.044

1

0.044

421.70

< 0.0001

 X 2 2

0.0006

1

0.0006

57.66

< 0.0001

 X 2 3

0.0008

1

0.0008

8.25

0.0166

 Residual

0.001

10

0.0001

  

 Lack of fit

0.0005

5

0.0001

0.97

0.5115

 Pure error

0.0005

5

0.0001

  

 Cor total

0.22

19

   

R2 = 0.9952

Adj. R2 = 0.9909

CV% = 0.17