Glossary
This glossary serves as a repository of information for phrases, terms, and symbols related to Statistical Process Control (SPC), process behavior charts, and continual improvement. Only phrases and terms with active links have publicly available definitions. Additional links will be activated over time.
Term
Assignable cause of exceptional variation
Average (see mean)
Average and Range chart
Common cause of routine variation
Control chart
Data
Distance to nearer specification
Experimental data
Experimental studies
Grand mean (or grand average)
Average range
Individual values
Individual values chart
Lower Specification Limit
Moving Range
Moving range chart
Numbers
Observational data
Observational studies
Operational definition
Probability density function
Process behavior chart
Process limits for Average and Range charts
Process limits for XmR charts
Rational subgroup
Rational subgrouping
Scaling factors using the average range
Scaling factors using the median range
Special cause
Square loss function
Statistical Process Control
Statistics
Three-sigma limits
Upper Specification Limit
Voice of the customer
Voice of the process
XmR chart
Symbol
Ave. mR or mR-bar
See process behavior chart
X̿
R̄
X chart
LSL
X-bar, X-tilde
mR
mR chart
f(X)
PBC
UAL, LAL, URL, LRL
UPL or UCL, LPL or LCL, URL
A2, D3, D4, E2
A4, D5, D6, E5
See assignable cause
SPC
3ᐧSigma(X)
USL
VoC
VoP