Hi,
I have performed a 2^3 Full factorial DOE with 2 replicates and two centre points (total 18 runs). The ANOVA results @ aplha value 0.05 are given as below (ANOVA pic also attached):
Estimated Effects and Coefficients for Nr of dry spots (coded units)
Term Effect Coef SE Coef T P
Constant 3.563 0.4370 8.15 0.000
Flow rate 0.875 0.437 0.4370 1.00 0.343
Vacuum during infusion 1.125 0.562 0.4370 1.29 0.230
Mould temp. 2.625 1.312 0.4370 3.00 0.015
Flow rate*Vacuum infusion 0.375 0.187 0.4370 0.43 0.678
Flow rate*Mould temp. 1.625 0.812 0.4370 1.86 0.096
Vacuum infusion*Mould temp. 1.125 0.563 0.4370 1.29 0.230
Flow rate*Vacuum infusion* 0.375 0.187 0.4370 0.43 0.678
Mould temp.
Ct Pt 1.438 1.3110 1.10 0.301
S = 1.74801 PRESS = 108.978
RSq = 67.11% RSq(pred) = 0.00% RSq(adj) = 37.87%
Analysis of Variance for Nr of dry spots (coded units)
Source DF Seq SS Adj SS Adj MS F P
Main Effects 3 35.6875 35.6875 11.8958 3.89 0.049
2Way Interactions 3 16.1875 16.1875 5.3958 1.77 0.223
3Way Interactions 1 0.5625 0.5625 0.5625 0.18 0.678
Curvature 1 3.6736 3.6736 3.6736 1.20 0.301
Residual Error 9 27.5000 27.5000 3.0556
Pure Error 9 27.5000 27.5000 3.0556
Total 17 83.6111
As the 'P' value for 'Curvature' is more than 0.05. Can i say that there is no curvature in my response variable and a linear model is good enough to describe the relationship between the variables and i do not need to proceed with a Response Surface Modelling DOE?
ANOVA also gives me 'Pure error', can anyone tell me what is the practicle meaning of 'Pure error' result in my case. Is it too big or low?
I also made 'Main effect plots' and 'Interaction plot' and the figures are attached. I dont understand why Mintab does not connect the line between the 'High value' and 'Low value' of main effect through the 'Centre point'?
thanks in advance
/tahir
I have performed a 2^3 Full factorial DOE with 2 replicates and two centre points (total 18 runs). The ANOVA results @ aplha value 0.05 are given as below (ANOVA pic also attached):
Estimated Effects and Coefficients for Nr of dry spots (coded units)
Term Effect Coef SE Coef T P
Constant 3.563 0.4370 8.15 0.000
Flow rate 0.875 0.437 0.4370 1.00 0.343
Vacuum during infusion 1.125 0.562 0.4370 1.29 0.230
Mould temp. 2.625 1.312 0.4370 3.00 0.015
Flow rate*Vacuum infusion 0.375 0.187 0.4370 0.43 0.678
Flow rate*Mould temp. 1.625 0.812 0.4370 1.86 0.096
Vacuum infusion*Mould temp. 1.125 0.563 0.4370 1.29 0.230
Flow rate*Vacuum infusion* 0.375 0.187 0.4370 0.43 0.678
Mould temp.
Ct Pt 1.438 1.3110 1.10 0.301
S = 1.74801 PRESS = 108.978
RSq = 67.11% RSq(pred) = 0.00% RSq(adj) = 37.87%
Analysis of Variance for Nr of dry spots (coded units)
Source DF Seq SS Adj SS Adj MS F P
Main Effects 3 35.6875 35.6875 11.8958 3.89 0.049
2Way Interactions 3 16.1875 16.1875 5.3958 1.77 0.223
3Way Interactions 1 0.5625 0.5625 0.5625 0.18 0.678
Curvature 1 3.6736 3.6736 3.6736 1.20 0.301
Residual Error 9 27.5000 27.5000 3.0556
Pure Error 9 27.5000 27.5000 3.0556
Total 17 83.6111
As the 'P' value for 'Curvature' is more than 0.05. Can i say that there is no curvature in my response variable and a linear model is good enough to describe the relationship between the variables and i do not need to proceed with a Response Surface Modelling DOE?
ANOVA also gives me 'Pure error', can anyone tell me what is the practicle meaning of 'Pure error' result in my case. Is it too big or low?
I also made 'Main effect plots' and 'Interaction plot' and the figures are attached. I dont understand why Mintab does not connect the line between the 'High value' and 'Low value' of main effect through the 'Centre point'?
thanks in advance
/tahir
Attachments

436.1 KB Views: 88

248.1 KB Views: 83
Last edited: