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Ch 6s MAR6466 on Final Exam

Terms in this set (30)

Use the information contained in the chart below to determine your answer.
Twenty samples of size 8 were taken from a stable process. From past studies of the process, you know that the overall mean is 42.5 and that the average of the samples range is 2.0. What is the upper control limit for the x-bar chart?

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43.25
A firm has an existing process that it would like to use for producing a part it will sell to an industrial customer. The customer requires that defective (out of specification) parts be kept to 3,000 parts per million (three-tenths of 1 percent) or less. A process capability study done on the process revealed that it has a process capability index (Cpk) of 1.00 for this part. What should the firm conclude from the study?
The process is capable, but just barely, and will require careful monitoring in order to meet customer requirements.
Suppose that you are a process manager in a manufacturing plant, and you suspect that there is a relationship between the room temperature of the plant and the weights of the plastic caps produced by an injection molding process. What quality improvement tool would you use to investigate this claim?
Scatter diagram
The specifications for the diameter of a molded part are 10 mm ± 0.5 mm. The actual average and standard deviation from 250 parts sampled is 10.1 mm and 0.1 mm, respectively. The process can be characterized as:
Capable.
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Management has decided that they must do something with the inability of the taillight assemblies to pass the quality specifications. Yet currently they do not know what areas they should look at. To help management in dealing with this issue, which of the following quality control tools would be most appropriate?
Cause-and-effect diagrams
Forty samples of 100 are taken, with the total number of defective units being 150. What is the upper control limit of the three sigma (z = 3) p-chart?
0.0945
Hugging in a control chart usually indicates:
Something is occurring that is masking natural variation.
A packaging plant is running a filling process where packages are filled with 24 oz. +/- 0.08 oz. A capability study reveals that the process mean is 24 oz. with a standard deviation of 0.02 oz. What is the capability of the packaging line?
1.33
A process can be said to be capable when:
The Cpk is greater than 1.5.
Fifteen samples of size 10 are taken from a stable process. The average of the sample means is 32.8, and the average range of the samples is 1.5. What is the upper control limit for the R chart? Use the information contained in the attached chart.

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2.666
We are experiencing a problem where a process keeps shifting over time. If we were to use a histogram to collect and display the resulting data, what type of shape would it most likely display?
Plateau-shaped distribution
Under what conditions would we be required to recalculate the parameters for an X-bar-R chart?
When we change the production process.
The width of a histogram showing a distribution of data indicates the __________ of the process that generated the distribution.
Predictability
"Pass/ fail" and "go/no go" are both examples of:
Attribute data
You are involved in the implementation of a quality improvement program. Your immediate goal is to identify what problems you should focus on (ideally you want to focus on those that give you the biggest bang for the buck). Which of the following quality control procedures is the most appropriate?
Pareto analysis
Which of the following tools is most appropriate when we are interested in determining if a process that was generating attribute-type data (pass/fail, good/bad) was under control?
p control chart
You are given the following data for taillight assemblies:

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Management has decided to carry out a Pareto analysis focusing on problem areas. Which of the following conclusions does the Pareto analysis support?
Management should focus attention on "inability to meet heat specs" and "scratched lens."
Forty samples of 100 are taken, with the total number of defective units being 150. What is the lower control limit for the three sigma (z = 3) p-chart?
0.000
Zanda Corp. has determined that it has too many products returned from customers. Zanda is interested in determining what factors or elements could contribute to the large number of returns. Which of the following quality tools would Zanda use to achieve this objective?
Fishbone diagram
The two types of data involved in quality control are:
Variables and attributes.
The Taguchi methods link process design to:
Process capability.
Which of the following categories of causes would be most appropriate for a Marriott (an international hotel chain) or McDonalds (an international fast food chain) or the local hair stylist?
Product, Price, Place, Promotion, People/personnel, Process, Physical evidence
The objective of statistical process control (SPC) is to:
Detect assignable cause variations versus normal random variations in the process.
You are given the following data for taillight assemblies:

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Which of the following tools does this data represent?
Check sheet
You have been given the following sample information that has been drawn from the last sample taken:

Mean of the sample: 12.50
Lower control limit for the range: 0
Upper control limit for the range: 10.6
Observations: 13, 12, 8, 10, 11, 16, 17, 8, 17, 18, 20, 14

Which of the following conclusions does this data support?
The sample is out of specification.
The specifications for the diameter of a molded part are 10 mm ± 0.5 mm. The actual average and standard deviation from 250 parts sampled is 10.1 mm and 0.1 mm, respectively. What is Cpk?
1.34
Sample means and ranges were obtained for five samples of 10 units per sample from a production process. Assume the process was considered to be in control during the period these samples were collected. The results are as follows:

Sample # Mean Range
1 10.58 0.23
2 9.97 0.25
3 9.99 0.21
4 10.23 0.28
5 10.23 0.28

What is the central line of the X chart for this process
10.20
Sample means and ranges were obtained for five samples of 10 units per sample from a production process. Assume the process was considered to be in control during the period these samples were collected. The results are as follows:

Sample # Mean Range
1 10.58 0.23
2 9.97 0.25
3 9.99 0.21
4 10.23 0.28
5 10.23 0.28

LCL for the three sigma X chart for the process is approximately (for a sample size of 10, A2 = 0.31):
10.12.
You have been given the following data:
Specification information: Anything between 10 and 20 units per order is acceptable.

Process Mean: 13
Upper limit of the process: 16
Lower limit of the process: 10

Using this information, which of the following conclusions is most appropriate?
The process is barely capable but not centered.
The specifications for the diameter of a molded part are 10 mm ± 0.5 mm. The actual average and standard deviation from 250 parts sampled is 10.1 mm and 0.1 mm, respectively. What is the process capability as measured by Cp?
1.67
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