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.

-Referring to Table 12-4, what is the expected number of employees with less than 1 year of training time and a high defect rate?
A) 4.17
B) 4.60
C) 5.28
D) 9.17

Question

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.
 
-Referring to Table 12-4, what is the expected number of employees with less than 1 year of training time and a high defect rate?
A) 4.17 
B) 4.60 
C) 5.28 
D) 9.17

Quizplus · Accepted Answer

To calculate the expected number of employees with less than 1 year of training time and a high defect rate, we need to look at the cells corresponding to <1 year of experience and >30 defects per 1,000 parts produced. The intersection of these cells is (3,3), which means there are 3 employees with less than 1 year of experience and more than 30 defects per 1,000 parts produced. To calculate the expected number of employees, we simply multiply the row total (27) for <1 year of experience with the column total (196) for >30 defects per 1,000 parts produced, and divide the result by the grand total (1000). Therefore, the expected number of employees with less than 1 year of training time and a high defect rate is (27*196)/1000 = 5.28, which is closest to choice C.

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