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Lowering the thickness of an expensive blow-molded
Chapter 13, Problem 33E(choose chapter or problem)
Problem 33E
Lowering the thickness of an expensive blow-molded container. Quality (Mar. 2009) presented a problem that actually occurred at a plant that produces a high-volume, blow-molded container with multiple layers. One of the layers is very expensive to manufacture. The quality manager at the plant desires to lower the average thickness for the expensive layer of material and still meet specifications. To estimate the actual thickness for this layer, the manager measured the thickness for one container from each of two cavities every 2 hours for 2 consecutive days. The data (in millimeters) are shown in the following tables. SPSS output for Exercise 13.32 a. Construct an R-chart for the data. b. Construct an x-chart for the data. c. Based on the control charts in parts a and b, c/omment on the current behavior of the manufacturing process. As part of your answer, give an estimate of the true average thickness of the expensive layer.
Questions & Answers
QUESTION:
Problem 33E
Lowering the thickness of an expensive blow-molded container. Quality (Mar. 2009) presented a problem that actually occurred at a plant that produces a high-volume, blow-molded container with multiple layers. One of the layers is very expensive to manufacture. The quality manager at the plant desires to lower the average thickness for the expensive layer of material and still meet specifications. To estimate the actual thickness for this layer, the manager measured the thickness for one container from each of two cavities every 2 hours for 2 consecutive days. The data (in millimeters) are shown in the following tables. SPSS output for Exercise 13.32 a. Construct an R-chart for the data. b. Construct an x-chart for the data. c. Based on the control charts in parts a and b, c/omment on the current behavior of the manufacturing process. As part of your answer, give an estimate of the true average thickness of the expensive layer.
ANSWER:
Step 1 of 5
The given information represents the thickness of an expensive blow-molded container.
(a) Construction of an R-chart for the data.
The following are the Minitab instructions to obtain the R-chart.
1. Access the Minitab worksheet ?le (BLOWMOLD) that contains the quality
data.
2. Click on the Stat button on the Minitab menu bar and then click on Control
Charts, Variables Charts for Subgroups, and click R....
3. Specify Observations for a subgroup are in one row of columns.
4. Click OK to produce the Minitab control chart.