The quality-control director for a clothing manufacturer wants to study the effect of operators and
machines on the breaking strength (in pounds) of wool serge material. A batch of the material is
cut into square-yard pieces and these are randomly assigned, three each, to all 12 combinations of
four operators and three machines chosen specifically for the experiment. The results are as
follows:

Operator Machine
I II III
A 115 111 109
114 108 110
119 114 107
B 117 105 110
114 102 113
113 106 114

Determine at the 5% significance level if there is a significant effect on the breaking strength
due to the interaction between the operator and machine.