Lean Six Sigma Green Belt Certification Measure Phase and Statistics 5

Question 1

What is the purpose of a box plot (box-and-whisker plot) in data analysis?

Accepted Answer

To show the five-number summary and identify outliers

Answer

A box plot displays the minimum, Q1, median, Q3, and maximum, providing a visual summary of distribution shape and outliers.

Question 2

During the Measure phase, a SIPOC diagram is primarily used to:

Accepted Answer

Provide a high-level view of the process and its boundaries

Answer

SIPOC maps Suppliers, Inputs, Process, Outputs, and Customers to establish scope and context before detailed measurement begins.

Question 3

Which term describes the smallest detectable difference that a measurement instrument can reliably distinguish?

Accepted Answer

Resolution (discrimination)

Answer

Resolution (or discrimination) is the smallest increment a gauge can detect; it should be at least 1/10 of the total process variation.

Question 4

A process collects data at regular intervals regardless of lot boundaries. This describes which sampling method?

Accepted Answer

Systematic sampling

Answer

Systematic sampling selects every nth unit at fixed intervals, making it time- or production-based rather than random at each draw.

Question 5

If a process has a long-term sigma level of 3.0, what is the approximate DPMO?

Accepted Answer

66,807

Answer

A 3-sigma process (long-term, with 1.5σ shift) corresponds to approximately 66,807 DPMO.

Lean Six Sigma Green Belt Certification Practice Test