Which of the following is not associated with descriptive statistics?
proportion
What technique determines whether a batch of goods should be accepted or rejected?
Acceptance sampling
What technique answers the question of whether the process is functioning properly or not?
Statistical process control
Statistical process control tools are used most frequently because
they are helpful in measuring and evaluating the quality of products
Common causes of variation are also known as __________________________.
random
The range is an example of what?
Traditional statistical tools
Variation in the production process leads to:
quality defects
The standard deviation is an example of what?
Traditional statistical tools
A process chart is a
graph that show whether a sample falls within the common or normal range
An x-bar chart is an example of what?
Statistical process control
For the standard normal distribution, how much confidence is provided within 2 standard deviations above and below the mean?
95.44%
The A2 factor includes how many standard deviations of ranges?
3
A p-chart is an example of what?
Statistical process control
P-charts are used to measure:
proportion of items in a sample that is defective
A c-chart is an example of what?
Statistical process control
An OC curve is an example of what?
Acceptance sampling
Causes of variation that can be identified and eliminated are called what?
Assignable
All processes will have what type of variation?
Random
What measures the central tendency of a set of data?
Mean
What measures the difference between the largest and smallest observations in a set of data?
Range
What measures symmetry of a distribution?
Skewness
Which of the following would imply that data observations are closely clustered around the mean?
Small range and small standard deviation
What is a distribution called when the same numbers of observations are below the mean as are above the mean?
Symmetric
What are the four most common control charts?
x-bar, R, p, c
On a control chart, what separates common from assignable causes of variation?
Control limits
The center line of a control chart represents what?
Mean
What is the first step that should be taken if an observation falls below the lower control limit on a control chart?
Search for assignable causes
Upper and lower control limits are usually set at how many standard deviations from the mean?
3.0
Assuming that data exhibit a normal distribution, control limits set at +- 3 standard deviations from the mean capture how much common variation?
99.74%
What is the probability of a Type I error for a control chart with limits set at +- 3 standard deviations from the mean?
0.26%
What is the term for the probability that a value falling outside the control limits is still due to normal variation?
Type I error
The different characteristics that can be measured by control charts can be divided into what two groups?
Variables and attributes
What is a control chart that monitors changes in the mean value of a process?
x-bar chart
What is a control chart that monitors changes in the dispersion or variability of a process?
R-chart
What is a control chart that monitors the proportion of defects in a sample?
p-chart
For which of the following would a control chart for attributes not be appropriate?
Length of metal rods
What are the two types of control charts for attributes?
p and c
What are the two types of control charts for variables?
x-bar and R
Consider a p-chart measuring the percentage of defective light bulbs. If the LCL is .
The process is out of control even though the variation is "good.
For a p-chart or c-chart, what is the implication of a negative value for the LCL?
The LCL can effectively be rounded up to 0.
What are preset ranges of acceptable quality characteristics?
Product specifications.
Product tolerances are often called
Product specifications
What process width is typically used when computing the process capability index Cp?
6 sigma
Setting up control charts to monitor whether a process is in control
does not guarantee process capability
What is the formula for the process capability index Cp?
specification width / process width
What process capability index (Cp) value implies that the process "exceeds minimal capability?
> 1
A process capability index (Cp) value of 1 means that what percent of products produced will fall within the specification limits?
99.74%
According to the textbook, the way to reduce the ppm defective is to
increase process capability
What is the relationship between Cp and Cpk?
Cp >= Cpk
Which company is known for coining the term "six-sigma?
Motorola Corporation
Six-sigma quality implies how many average defects per million?
3.4
What are the two aspects to implementing the six-sigma concept?
technical tools and people involvement
In six-sigma programs, individuals who have extensive training in the use of technical tools and are responsible for carrying out the implementation of Six Sigma are __________________.
black belts
In six-sigma programs, individuals are given __________________ titles that reflect their skills in the six-sigma process.
martial arts
The Six Sigma approach is organized around a _______ plan known as ________.
five step DMAIC
The person that comes from the top ranks of the organization and is responsible for providing direction and overseeing all aspects of a six-sigma implementation process is called a ________________________.
champion
When should 100% inspection be used?
When the expected cost of a defective item exceeds the cost of inspecting a unit
What is a graph that shows the probability or chance of accepting a lot given various proportions of defects in the lot?
OC curve
Single sampling plan is when
a random sample is drawn from every lot.
According to the text, what percent of defects are consumers generally willing to accept?
1-2%
Which of the following is the least important point to perform inspection?
Just after costly processing
What is the only service company to have won the Malcolm Baldrige National Quality Award twice?
Ritz-Carlton
Suppose that you want to measure the percentage of candles that are cut longer than 9 inches. Which control chart would be appropriate?
p-chart
What is the upper control limit for a c-chart if the total defects found over 20 samples equals 150?
15.72
Suppose that Matt wants to use a process control chart to monitor the number of different types of mistakes that he makes when giving motivational speeches to student groups. Which control chart would be most appropriate?
c-chart
Suppose that you have calculated the control limits for a p-chart to be the following:
LCL = 0.02 and UCL = 0.08.
Today, you took 10 samples of 20 units each. The first nine samples each had one defect. The last sample had zero defects. What can you concl
the process is out of control
Suppose that you want to monitor the variability in ounces of a process that fills beer cans. Which control chart would be appropriate?
a) x-bar chart
R-chart
What is the lower control limit for a c-chart if the average number of defects found over 320 samples is equal to 16?
4
Each day for two workweeks (10 days total), George weighs 4 bags from that day's production. If the average of the means is 14 oz. and the average range is 0.4 oz., what is the lower control limit for an x-bar chart for this process?
13.7084 oz.
If the upper control limit for a c-chart is 28 and the lower control limit is 4, what is the average number of defects per sample?
16
Suppose that you want to monitor the average ounces of a process that fills beer cans. Which control chart would be appropriate?
x-bar chart
What is the upper control limit for a c-chart if the total defects found over 200 samples equals 32?
1.36
Ritz-Carlton employees are empowered to spend up to how much money on the spot to correct any customer complaint?
$2000
What program at Intel enforces the policy to make chips in the same way at all facilities?
copy-exactly