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Fundamentals of Experimental Design  461

           TABLE 12.22 Example 12.10 with Missing Data

           A        B      C       AB       AC      BC      ABC      Y
            1      1       1        1        1       1       1       60

             1     1       1        1        1       1        1      72
            1       1      1        1        1       1        1      y1
             1      1      1        1        1       1       1       68
            1      1        1       1        1       1        1      52

             1     1        1       1        1       1       1       83
            1       1       1       1        1       1       1       45
             1      1       1       1        1       1        1      y2





                                                abc
                          bc
                                                 X

              c                       ac
           +



                           X                      ab
            C                                         +
                           b
                                                 B
            –
                                       a
               (1)         A               –
                –                      +
           Figure 12.22  Missing data points in Example 12.10.



               Since the experimental runs b and abc are missing, we cannot calculate
             the elementary effects ab   b and abc   bc, but we still have data to calcu-
             late the elementary effects a   1 and ac   c, so we will use the following par-
             tial average of a   1 and ac   c to estimate A, that is,


                                      c)   ⎡
                                                             ⎤
                    A   1 ⎡ ( a 1)   ( ac  ⎤ ⎦  2 ⎣ ( 72  60)  ( 83  52)    2115
                                                                  .
                                                             ⎦
                                          1
                        2 ⎣
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