X bar R Charts - d2 constant, "g" and "m" definitions

In Xbar R charts etc. determining values for d2 based on definitions of "g" and "m" is straightforward, as the d2 table (MSA III, p. 195) defines them as "Number of Subgroups" and "Subgroup Size" respectively.

In MSA the K1 and K2 constants are dependent on the d2 value, where "g" and "m" are determined based on "number of range calculations" and "number of appraisers". In other statistical applications this "translation" of parameters into "g" and "m" values also can be seen.

I have great difficulties with this "translation" each time I have to derive the correct d2 value on various occasions.

Anyone who can clarify this once and for all?

I would really appreciate some clear examples or guidelines on the "g" and "m" parameter so that my slow brain can grasp this.

Re: d2 constant, "g" and "m" definitions

As an example of what I meant by "translations" on "g" and "m" factors see MSA III manual p. 115, where K2 constant has a "g" = 1, "since there is only one range calculation"....

Re: d2 constant, "g" and "m" definitions

Morten, not sure if this is what you want:

Assuming 10 parts, 3 ops and 3 trials
formula: RBar/d2; Ki= 1/d2

K1: EV
Considering the variation due to equipment. Each set of trials by each appraiser forms a subgroup. So we have 30 subgroups and 30 subgroup ranges. Each subgroup has 3 readings(= no of trials). We then use the overall range RBar to calculate EV.
Subgroup size (m)= 3
No of subgroups (g)=30
d2* = 1.69257
K1 = 1/d2* = 0.5908

K2: AV
For the purpose of calculating appraiser variation, using RBar/d2 formula, we use a single subgroup of n readings (assuming n operators) where each value in the subgroup is the grand average of each appraiser (XBar_a, XBar_b,...: regardless of parts and trials). There is only one range calculation. The range of this subgroup is the XBarDiff. Therefore there is only 1 subgroup and the subgroup size = no of appraisers.

Subgroup size (m)= 3 (no of appraisers)
No of subgroups (g)=1
d2* = 1.91155
K2 = 1/d2* = 0.5231


K3: PV
For Calculating Part Variation, there in only one subgroup of 10 values, each value in the subgroup is the part average (regardless of appraiser and trials)- one range calculation.

Subgroup size (m)= 10 (no of parts)
No of subgroups (g)=1
d2* = 3.17905
K3 = 1/d2* = 0.3146

Also:
https://elsmar.com/Forums/showthread.php?t=6066

erm.. that's very helpful..

How do I go about 24 trials, 2 operators, 23 parts?

Is there any spreadsheet or table out there that provides the d2 values for all different subgroup size? I am in a bit of a trouble now for not having MSA manual.