topic Re: SPC Control Chart for Attribute no Sigma Report in Discussions

SPC Control Chart for Attribute no Sigma Report

WebDesignesCrow — Wed, 16 Aug 2023 06:49:37 GMT

Hello Expert,

I noticed that when I'm using Control Chart for Attribute, I cannot turn on Sigma Report.

How can I display how many N in this chart without using scripting?

The N value is important for us to communicate to management & analysis can be replicated without scripting.

(If in Control Chart for Variable, the Sigma Report will show the N value. So, we could say 7 lots will fail out of how many)

I'm using JMP 17

Re: SPC Control Chart for Attribute no Sigma Report

jthi — Wed, 16 Aug 2023 07:18:02 GMT

According to documentation it is only available for variables chart

Show Sigma Report ( Quality and Process Methods > Control Chart Builder > Control Chart Builder Options > Control Chart Builder Red Triangle Menu Options )

(Available only for Shewhart Variables charts.) Shows or hides the Process Sigma Report, which is a table of sigma values. The Process Sigma Report contains the overall sample size, number of subgroups, sample mean, overall sigma, within sigma, and stability index. For three way control charts, the between-sigma and between-and-within sigma values are also shown. If a phase variable is specified, a set of values is given for each phase.

Maybe you could for example use other platform to calculate N (Distribution/Tabulate/...) and then use Combine Windows to combine them to create a Dashboard

Re: SPC Control Chart for Attribute no Sigma Report

WebDesignesCrow — Wed, 16 Aug 2023 07:44:09 GMT

Thank you @jthi for the suggestion.

Since it only available in variable chart, then I would just use I-MR chart (without MR).

The calculated limits & alarm rate are the same (I think it is because the Laney's method normalize the MR to estimate the sigma then transform back).

Three-way chart is a powerful tool (for analyst) but it's hard to get high-level people to understand it.