Symbols or Acronyms
What is the symbol for a standard deviation?
A discrete measurement system is acceptable when this is met
What is Effectiveness >= 90%?
Collecting a portion of all the data
What is sampling?
Management asking for explanations or actions in response to common cause variation
What is an example of tampering?
68, 95, 99
What is the % between 1s, 2s, and 3s respectively? (Normal Curve)
What is the symbol for sample size?
A continuous measurement system is acceptable when this is met
What is P/TOT <= 10%?
Collecting what is convenient
What is an example of sampling bias?
Variation that is always present to some degree in the process
What is Common Cause variation?
Looking for what is different between individual points
What action is taken when investigating Special Cause?
UCL
What is the Upper Control Limit?
Two or more people measuring the same characteristic in the same way get the same answer
What is Reproducibility?
Each unit has the same chance of being selected
What is random sampling?
Get timely data, take immediate action, and determine what was different
What are steps in response to Special Cause variation?
Checksheet, frequency plot, concentration diagram
What are data collection forms?
d
What is the symbol for precision - or half interval width?
The measurement method or device does not vary much from the actual value
What is Accuracy?
Randomly sampling a proportionate number from each group
What is stratified random sampling?
Stratify and/or Disaggregate data
What are investigation techniques for Common Cause variation?
Sample every nth one
What is systematic sampling?
P/TOT
What is Precision to Total?
Labeling parts in a way to record measurements and remove possible operator bias
What is blind marking?
Proportion defective (p), precision (d)and confidence level
What are the required "inputs" for estimating sample size for a proportion?
Stable and predictable process
What is a process with common cause variation?
Clarify data collection goals, develop operational definitions, validate measurement system, collect data, improve measurement consistency
What are the 5 Steps for Data Collection?