R Programming Language Certification Quality Control & Assurance 5

Question 1

In R, which `qcc` chart type uses the median moving range to estimate process variability, making it robust to non-normality?

Accepted Answer

xbar.one chart with MMR

Answer

The Xbar.one (individuals) chart can use the median moving range instead of the average moving range as a more robust estimator of σ for non-normal data.

Question 2

What R function generates a probability plot (normal probability plot) used to assess whether process data follows a specified distribution?

Accepted Answer

qqnorm() or qqplot()

Answer

`qqnorm()` creates a normal Q-Q plot comparing data quantiles to theoretical normal quantiles; `qqplot()` extends this to any reference distribution.

Question 3

In the `SixSigma` R package, `ss.ca.cp()` computes the Cp index. What additional data argument beyond the sample vector is required?

Accepted Answer

LSL and USL specification limits

Answer

Cp requires both the lower specification limit (LSL) and upper specification limit (USL) to compute the ratio of the specification width to the process spread.

Question 4

When applying the `demerit()` function in R for weighted defect scoring, what differentiates a 'critical' defect weight from a 'minor' defect weight?

Accepted Answer

Critical defects receive much higher weights (e.g., 100) vs minor (e.g., 1)

Answer

Demerit systems assign severity weights (e.g., 100 for critical, 50 for major, 10 for minor, 1 for incidental) so that weighted defect counts reflect true quality impact.

Question 5

In R, what is the correct way to perform a multi-variate control chart (T² chart) for monitoring two correlated quality characteristics simultaneously?

Accepted Answer

mqcc(data, type='T2')

Answer

`mqcc()` from the `qcc` package handles multivariate quality control, with `type='T2'` specifying the Hotelling T² control chart for correlated variables.

R Programming Language Certification Practice Test

R Programming Language Certification Practice Test

R Programming Language Certification Quality Control & Assurance 5