Examples
Examples
Try the starting example
- Equal-sized subgroup readings JSON (measurement units)
- [[9,11],[10,12],[11,13]]
- User-selected published A2 constant (dimensionless)
- 1.88
- User-selected published D3 constant (dimensionless)
- 0
- User-selected published D4 constant (dimensionless)
- 3.267
- Grand subgroup mean (measurement units)
- 11
- Mean subgroup range (measurement units)
- 2
- X-bar lower limit (measurement units)
- 7.24
- X-bar upper limit (measurement units)
- 14.76
- R lower limit (measurement units)
- 0
- R upper limit (measurement units)
- 6.534
Try another scenario
- Equal-sized subgroup readings JSON (measurement units)
- [[8,12],[9,13],[10,14]]
- User-selected published A2 constant (dimensionless)
- 1.88
- User-selected published D3 constant (dimensionless)
- 0
- User-selected published D4 constant (dimensionless)
- 3.267
- Grand subgroup mean (measurement units)
- 11
- Mean subgroup range (measurement units)
- 4
- X-bar lower limit (measurement units)
- 3.48
- X-bar upper limit (measurement units)
- 18.52
- R lower limit (measurement units)
- 0
- R upper limit (measurement units)
- 13.068
Calculation method
Calculation method
Grand subgroup mean (measurement units)
Mean of subgroup means.
Mean subgroup range (measurement units)
Mean(max(group)-min(group)).
X-bar lower limit (measurement units)
grandMean-A2*Rbar.
X-bar upper limit (measurement units)
grandMean+A2*Rbar.
R lower limit (measurement units)
D3*Rbar.
R upper limit (measurement units)
D4*Rbar.
Symbols and units
- a
- Equal-sized subgroup readings JSON (measurement units)
- b
- User-selected published A2 constant (dimensionless)
- c
- User-selected published D3 constant (dimensionless)
- d
- User-selected published D4 constant (dimensionless)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Classical rational-subgroup X-bar/R chart. Constants must match subgroup size; default constants are for n=2. Tool must display supplied constants and group size and reject mismatch if built-in table mode is used. No stability declaration. Supported limits: 2..200 subgroups, equal n in 2..10; A2>0; 0<=D3<=D4. Custom constants explicitly user supplied.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
Background reading; this does not imply endorsement or independent review of SumFizz.