Fundamentals Flashcards

What is the difference between Cp and Cpk?

Answer: Cp ignores centering; Cpk accounts for both spread and centering

Cp only measures whether the process spread fits within specifications, while Cpk also accounts for how well the process is centered between the limits.

Which of the following is NOT one of Walter Shewhart's two types of variation?

Answer: Structural causes

Shewhart identified chance causes (common) and assignable causes (special); 'structural causes' is not part of his framework.

A process producing 3.4 defects per million opportunities operates at what sigma level?

Answer: 6 sigma

Six Sigma quality is defined as 3.4 DPMO, which accounts for a 1.5-sigma long-term shift in the process mean.

Which type of data would you use an Individuals and Moving Range (I-MR) chart for?

Answer: Continuous data collected one observation at a time

The I-MR chart is designed for continuous variable data where only one measurement is produced at each time point.

The term 'voice of the process' (VOP) in SPC refers to:

Answer: What control charts reveal about process behavior

VOP refers to what the data and control charts tell us about how the process is actually performing.

If a process has Cpk = 1.0, what percentage of output is expected to be within specification?

Answer: 99.73%

A Cpk of 1.0 corresponds to the process mean being exactly 3 sigma from the nearest specification limit, yielding 99.73% within spec.

Which SPC tool is used to identify and prioritize the most significant causes of a quality problem?

Answer: Pareto chart

A Pareto chart ranks defect categories by frequency, helping teams focus on the 'vital few' causes that account for most problems.