I have been having the same problem as poster Hodgess, below. It appears
that her question was never answered, so I would like to share a solution
with the community.
The problem is the (apparent?) inability to produce moving range process
behavior (a.k.a. "control") charts with individuals data in the package
"qcc" (v. 2.0). I have also struggled with the same limitation in package
"IQCC" (v. 1.0).
The package "qAnalyst" (v. 0.6.0) provides an option to produce a moving
range chart with individuals data. The example given in the qAnalyst manual
for function spc yields an individuals chart:
> #i-chart, moving range to estimate st. dev. is equal to 2 points with
testType=1,
> data(rawWeight)
> ichart=spc(x=rawWeight$rawWeight, sg=2, type="i", name="weight",
testType=1)
> plot(ichart)
> summary(ichart)
Changing "type = 'i'" to "type = 'mr'" yields the moving chart:
> mrchart = spc(x = rawWeight$rawWeight, sg = 2, type = "mr", name =
"weight", testType = 1)
> plot(mrchart)
> summary(mrchart)
In separate tests, I have confirmed that qAnalyst correctly computes natural
process limits (a.k.a. "control limits") for X-bar and R charts, using the
average of the subgroup means. I have not yet checked the calculations for
the ImR or other charts.
An additional difference between these packages is that qAnalyst uses the
lattice library to generate output, while the other two packages appear to
use the (traditional) graphics library.
Regards,
Tom
On Tue, 10 Nov 2009 23:39:23 -0600, Erin Hodgess
<erinm.hodgess_at_gmail.com<erinm.hodgess_at_gmail.com?Subject=Re:%20[R]%20%20plotting%20moving%20range%20control%20chart>>
wrote:
> Dear R People:
>
> I am using qcc for a quality control class.
>
> I have used qcc with type "xbar.one" for individuals but cannot determine
> how to plot a moving range control chart.
>
> Has anyone done that, please?
>
> Thanks,
> Erin
>
> --
> Erin Hodgess
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: erinm.hodgess_at_gmail.com
>
>
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