Page 430 - Six Sigma Demystified

410 Six SigMa DemystifieD

where S is the average sigma, and c is a function of n (tabulated in Appendix
4
6). Note: Some authors prefer to write this as

UCL = S B 4
S

LCL = S B 3
S
where B and B are a function of n (tabulated in Appendix 6).
3 4

X-Bar Chart

Minitab

Use Stat\Control Chart\Variable Charts for Subgroups\XBar-R.

Options

Use Options\Display to specify plotted subgroups.
Use Scale\Time\Stamp to set column for x-axis labels.
Use Options\Parameters for predefined centerline and control limits.
Use Options\Estimate to omit subgroups from calculations.

Use Options\Stages to define control regions.
Use Options\Test to apply relevant run-test rules.

Excel

Using Green Belt XL Add-On

Use New Chart\X-Bar or Range Chart or X-Bar and Sigma Chart.

Options
Use Data Range to specify plotted subgroups.
Use Options\Title\Label to set column for x-axis labels.

Use Options\Control Limits for predefined centerline and control limits, to omit
subgroups from calculations, and to define control regions.