A manufacturing company produces part 2205 for the aerospace industry. This particular part can be manufactured using 3 different production processes. The management wants to know if the quality of the units of part 2205 is the same for all three processes. The production supervisor obtained the following data: The Process 1 had 29 defective units in 240 items; Process 2 produced 12 defective units in 180 items and

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Process 3 manufactured 9 defective units in 150 items. At a significance level of .05, we performed a chi-square test to determine whether the quality of the items produced appear to be the same for all three processes. What is the null hypothesis?

A. H0: The number of defectives produced is independent of the production process used.

B. H0: The row and column variables are associated with each other.

C. H0: The proportion of defective units produced by the three production processes is the same.

D. Both A and C are correct or at least acceptable way of stating the null hypothesis.

E. A, B and C are all acceptable ways of stating the null hypothesis.