Page 311 - Six Sigma Demystified

Part 3 s i x s i g m a to o l s 291

Note: Some authors prefer to write this as

UCL MR = MRD 4 LCL MR = MRD 3

Individual-X Chart

Minitab

Use Stat\Control Chart\Variable Charts for Individuals\I-MR or Individuals.

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.
Note: When the normality assumption is not met, the data must be transformed
(using Stat\Quality Tools\Johnson Transformation).

Excel

Using Green Belt XL Add-On

Use New Chart\Individual-X and Moving Range 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.
Use Options\Analysis\Auto Drop checkbox to automatically remove out-of-
control groups from the control limit calculations (they are still displayed on
the chart).
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