Table 3 Analysis of variance (ANOVA) results of the main effects

Source

Sum of Squares

d.f.

Mean Square

F

p

 Iodine Concentration

20.4

3

6.8

675.9

<  0.001

 Radiation Dose Level

40.3

2

20.2

2003.1

<  0.001

 Tube Potential

15.9

1

15.9

1584.1

<  0.001

 Reconstruction Algorithm

65.5

2

32.8

3254.6

<  0.001

Source

Sum of Squares

d.f.

Mean Square

F

p

 Iodine Concentration

27.5

3

9.2

3754.9

<  0.001

 Radiation Dose Level

14.9

2

7.4

3047.7

<  0.001

 Tube Potential

7.7

1

7.7

3153.0

<  0.001

 Reconstruction Algorithm

2.1

2

1.0

426.3

<  0.001

Source

Sum of Squares

d.f.

Mean Square

F

p

 Iodine Concentration

68.6

3

22.9

1556.9

<  0.001

 Radiation Dose Level

49.9

2

25.0

1700.0

<  0.001

 Tube Potential

23.0

1

23.0

1565.7

<  0.001

 Reconstruction Algorithm

7.5

2

3.7

254.3

<  0.001

Source

Sum of Squares

d.f.

Mean Square

F

p

 Iodine Concentration

98,595

3

32,865

76,477.7

<  0.001

 Radiation Dose Level

159,722

2

79,861

185,839.2

<  0.001

 Tube Potential

21,144

1

21,144

49,202.4

<  0.001

 Reconstruction Algorithm

64,641

2

32,320

75,210.3

< 0.001

Source

Sum of Squares

d.f.

Mean Square

F

p

 Iodine Concentration

0.127

3

0.042

1998.5

< 0.001

 Radiation Dose Level

0.079

2

0.039

1866.1

<  0.001

 Tube Potential

0.032

1

0.032

1520.1

< 0.001

 Reconstruction Algorithm

0.021

2

0.010

498.2

< 0.001