The article “An Investigation into the Ball Burnishing of Aluminium Alloy 6061-T6"' (M. El-Axir, J Engineering Manufacture, 2007:1733-1742) presents the results of study that investigated the effects of three burnishing factors on the reduction in diameter of the workpiece (in /im). The factors are A: Burnishing speed, B: Burnishing force, and C: Burnishing feed. The results presented in the following table form a 23 factorial design (some additional results are omitted).

A |
B |
C |
Reduction |

-1 |
-1 |
-1 |
570 |

1 |
-1 |
-1 |
353 |

-1 |
1 |
-1 |
778 |

1 |
1 |
-1 |
769 |

-1 |
-1 |
1 |
544 |

1 |
-1 |
1 |
319 |

-1 |
1 |
1 |
651 |

1 |
1 |
1 |
625 |

a. Compute estimates of the main effects and the interactions.

b. Is it possible to compute an error sum of squares? Explain.

c. Are any of the interactions among the larger effects? If so, which ones?

d. Someone claims that the additive model holds. Do the results tend to support this statement? Explain.

Chapter 11 REPEATED MEASURES/WITHIN-SUBJECTS DESIGN ● two separate scores are obtained for each person in the sample ○ ex. group measured before therapy and after therapy ● the same group of subjects is used ● matched-subjects design = each person in one sample is matched with a person in the other sample...