Hello everyone,
Control limits for R charts are formed using
UCL= D4 Rbar
LCL= D3 Rbar
Where D4 and D3 are values read from tables (for a specific sample
size). Could anyone give me a reference where I might find tabulated
values for D3 and D4 for really large sample sizes (i.e. n from 100 to
around 5000 and possibly beyond!). The largest sample size I can find
tables for is 100.
Similarly for Xbar charts, if I wanted to calculate sigma_x using
Rbar/d2.....are there tables which provide values for d2 for really
large sample sizes?
The nature of my problem means that it is not possible to reduce the
sample size.
[In, for example, Minitab we cannot construct control charts when
n>100].
Kind Regards,
Kim
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