R Programming Language Certification Quality Control & Assurance 3

Question 1

In R, which control chart type is most appropriate for monitoring the proportion of nonconforming items in variable-sized subgroups?

Accepted Answer

p chart

Answer

The p chart monitors the proportion of nonconforming items and accommodates variable subgroup sizes, unlike the np chart which requires fixed subgroup sizes.

Question 2

When running `gage.rr()` in R's `SixSigma` package, a %Contribution of measurement system above what threshold is generally considered unacceptable?

Accepted Answer

30%

Answer

A measurement system %Contribution (or %Study Variation) above 30% is generally unacceptable; below 10% is acceptable; 10–30% may be acceptable depending on context.

Question 3

Which R function from the `qcc` package generates a Pareto chart for quality defect analysis?

Accepted Answer

pareto.chart()

Answer

`pareto.chart()` in the `qcc` package creates a Pareto chart showing defect categories sorted by frequency with a cumulative percentage line.

Question 4

In R, what is the primary purpose of Western Electric (WECO) rules applied via `qcc`?

Accepted Answer

To detect non-random patterns beyond just points outside control limits

Answer

WECO rules detect non-random patterns (runs, trends, stratification) within control limits that a single 3-sigma rule alone would miss.

Question 5

In the context of R-based SPC, what does 'Phase I' analysis refer to?

Accepted Answer

Retrospective analysis to establish baseline control limits from historical data

Answer

Phase I SPC involves retrospective analysis of historical data to estimate process parameters and establish control limits for future Phase II monitoring.

R Programming Language Certification Practice Test

R Programming Language Certification Practice Test

R Programming Language Certification Quality Control & Assurance 3