请教高手DOE问题

在DOE分析结果中有coded units模式和uncoded units模式，当去除一些非显著因子时，为什么coded units模式的系数不变，而uncoded units模式的系数改变，具体如下：

Factorial Fit: RESULT versus A, B, C, D

Estimated Effects and Coefficients for RESULT (coded units)

Term Effect Coef
Constant 42.813
A 9.375 4.687
B 11.375 5.688
C 14.125 7.063
D 2.125 1.063
A*B 9.125 4.563
A*C 16.375 8.187
A*D 14.875 7.437
B*C -5.625 -2.813
B*D 0.375 0.188
C*D -2.375 -1.187
ABC -8.375 -4.188
ABD 8.125 4.063
ACD -10.125 -5.062
BCD -6.625 -3.313
ABC*D -8.375 -4.188


S = *


Analysis of Variance for RESULT (coded units)

Source DF Seq SS Adj SS Adj MS F P
Main Effects 4 1685.3 1685.3 421.3
2-Way Interactions 6 2440.4 2440.4 406.7
3-Way Interactions 4 1130.3 1130.3 282.6
4-Way Interactions 1 280.6 280.6 280.6
Residual Error 0 *
Total 15 5536.4


Estimated Coefficients for RESULT using data in uncoded units

Term Coef
Constant _-22.8333_
A _-178.167_
B _-52.8333_
C _ 24.4167_
D _ 4.66667_
A*B _-82.8333_
A*C _60.2500_
A*D _21.8333_
B*C _23.0833_
B*D _11.1667_
C*D _-1.58333_
ABC _27.9167_
ABD _16.6667_
ACD _-6.75000_
BCD _-4.41667_
ABC*D _-5.58333_



Factorial Fit: RESULT versus A, B, C, D

Estimated Effects and Coefficients for RESULT (coded units)

Term Effect Coef SE Coef T P
Constant 42.813 4.199 10.19 0.000
A 9.375 4.687 4.199 1.12 0.315
B 11.375 5.688 4.199 1.35 0.234
C 14.125 7.063 4.199 1.68 0.153
D 2.125 1.063 4.199 0.25 0.810
A*B 9.125 4.563 4.199 1.09 0.327
A*C 16.375 8.187 4.199 1.95 0.109
A*D 14.875 7.438 4.199 1.77 0.137
B*C -5.625 -2.812 4.199 -0.67 0.533
B*D 0.375 0.188 4.199 0.04 0.966
C*D -2.375 -1.188 4.199 -0.28 0.789


S = 16.7977 R-Sq = 74.52% R-Sq(adj) = 23.55%


Analysis of Variance for RESULT (coded units)

Source DF Seq SS Adj SS Adj MS F P
Main Effects 4 1685 1685 421.3 1.49 0.331
2-Way Interactions 6 2440 2440 406.7 1.44 0.353
Residual Error 5 1411 1411 282.2
Total 15 5536


Unusual Observations for RESULT

Obs StdOrder RESULT Fit SE Fit Residual St Resid
13 12 76.0000 55.1875 13.9279 20.8125 2.22R

R denotes an observation with a large standardized residual.


Estimated Coefficients for RESULT using data in uncoded units

Term Coef
Constant _-22.8333_
A _-68.4792_
B _ 18.9375_
C _ 24.4167_
D _4.6667_
A*B _4.56250_
A*C _ 16.3750_
A*D _ 4.95833_
B*C _-5.62500_
B*D _0.12500_
C*D _-1.58333_


Alias Structure
I
A
B
C
D
A*B
A*C
A*D
B*C
B*D
C*D