Solution Found!
Defective plastic mold. A company that manufactures
Chapter 13, Problem 82SE(choose chapter or problem)
Defective plastic mold. A company that manufactures plastic molded parts believes it is producing an unusually large number of defects. To investigate this suspicion, each shift drew seven random samples of 200 parts, visually inspected each part to determine whether it was defective, and tallied the primary type of defect present (Hart, 1992). These data are presented in the table at the top of the next page.
a. From a statistical perspective, are the number of samples and the sample size of 200 adequate for constructing a p-chart for these data? Explain.
b. Construct a p-chart for this manufacturing process.
c. Should the control limits be used to monitor future process output? Explain.
d. Suggest a strategy for identifying the special causes of variation that may be present.
Questions & Answers
QUESTION:
Defective plastic mold. A company that manufactures plastic molded parts believes it is producing an unusually large number of defects. To investigate this suspicion, each shift drew seven random samples of 200 parts, visually inspected each part to determine whether it was defective, and tallied the primary type of defect present (Hart, 1992). These data are presented in the table at the top of the next page.
a. From a statistical perspective, are the number of samples and the sample size of 200 adequate for constructing a p-chart for these data? Explain.
b. Construct a p-chart for this manufacturing process.
c. Should the control limits be used to monitor future process output? Explain.
d. Suggest a strategy for identifying the special causes of variation that may be present.
ANSWER:Step 1 of 14
(a)
Obtain the sample size determination for monitoring a process proportion as shown below:
Choose n, such that 
Where, n is the sample size and 
The estimate of the process proportion p 
Thus, the value of 
