30 Questions
What is the main goal of Statistical Process Control (SPC)?
To stabilize the process and meet customer requirements
What is the purpose of using small Post-it® notes on a flowchart?
To increase clarity and ease of change
When can improvement efforts begin in a process?
After stabilizing and making the process predictable
What is the significance of control charts and histograms in a process?
To demonstrate improvements in the process
How should detailed sub-processes be managed in a flowchart?
Move them to additional pages
Where should every person or department involved in delivering the product or service be listed on a flowchart?
Across the top of the flowchart
What are the two outcomes for any improvement effort?
Center the distribution over the target value and reduce the spread of the distribution.
How do customers specify their requirements for targets and tolerances?
Target and a bilateral tolerance
What are specification limits used to determine?
Goal posts and process capability
How are control limits in control charts different from specification limits?
Control limits are based on customer expectations, while specification limits focus on process capability.
What are the three key characteristics of distributions mentioned in the text?
Center, spread, and shape
How can you monitor the outcomes of improvement efforts according to the text?
By analyzing histograms
What does a shape parameter of less than 1 in failure rate describe?
Decreasing failure rate (infant mortality)
What does a shape parameter of 3.6 in failure rate approximate?
Normal distribution
What does the scale parameter (characteristic life) signify?
Age at which 63.2% of units will have failed
How can one determine when a certain percent of parts will have failed using Weibull Probability Plot?
Using specification limits
In the given example, what percentage of parts will have failed by time 27?
10%
How can one calculate the actual defect rate in parts per million (PPM)?
Using the standard deviation and specification limits
What does the Cpk measure in statistical process control?
If data fits between the upper and lower specification limits
If Cp is less than Cpk, what does it indicate?
Data is centered but does not fit between the spec limits
What is the main difference between Pp and Ppk in statistical process control?
Pp uses an estimation of standard deviation, while Ppk uses the actual standard deviation of the data
In statistical process control, what does Weibull analysis excel at?
Working well with failure rates and small samples
What corrective action should be taken if Cp = Cpk and both are between 1.0 and 1.33?
Improve the process to reduce variation
What type of data is Weibull analysis especially suited for?
Failure rates data (e.g., time until failure)
What is the purpose of the XbarS chart?
To monitor and evaluate process performance using time, length, weight, or cost when there are 6–25 samples per period
What should be done to view charts for each data set in the X Chart Formulas Data Input Sheet?
Click on the arrows
When is the Xmr or c, p, u, np chart dashboard opened?
After entering data into the data input sheet
What do the control chart dashboards in QI Macros contain?
An instruction sheet, a data input sheet, and a sheet for each available control chart and a run chart
Which type of chart is used to monitor and evaluate process performance when there are more than 25 samples per period?
Range Chart
What action should be taken to create a dashboard with each available control chart?
Click on the Create Dashboard icon
Learn about using flowcharts to define and refine the process FISH steps, including refining the process, improving quality indicators, implementing changes, checking for stability and recognizing achievements. Understand the symbols used in flowcharts to visualize process flows.
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