TABLE 12-4
One Criterion Used to Evaluate Employees in the Assembly

TABLE 12-4
One criterion used to evaluate employees in the assembly section of a large factory is the number of defective pieces per 1,000 parts produced. The quality control department wants to find out whether there is a relationship between years of experience and defect rate. Since the job is repetitious, after the initial training period any improvement due to a learning effect might be offset by a loss of motivation. A defect rate is calculated for each worker in a yearly evaluation. The results for 100 workers are given in the table below.
$$\begin{array}{l}\text {\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad Years Since Training Period }\\\begin{array} { r | r r c } & \text { < 1 Year } & 1 - 4 \text { Years } & 5 \text { - 9Years } \\\hline \text { High } & 6 & 9 & 9 \\\text { Defect Rate: Average } & 9 & 19 & 23 \\\text { Low } & 7 & 8 & 10\end{array}\end{array}$$
-Referring to Table 12-4, find the rejection region necessary for testing at the 0.05 level of significance whether there is a relationship between defect rate and years of experience.

A) Reject H₀ if ?² > 16.919
B) Reject H₀ if ?² > 9.488
C) Reject H₀ if ?² > 11.143
D) Reject H₀ if ?² > 15.507