Lean Six Sigma Green Belt Certification Measure Phase and Statistics 2

Question 1

A process has a mean of 50 and a standard deviation of 5. What is the coefficient of variation (CV)?

Accepted Answer

10%

Answer

CV = (standard deviation / mean) × 100 = (5/50) × 100 = 10%.

Question 2

Which measurement scale allows calculation of meaningful ratios between values?

Accepted Answer

Ratio

Answer

Ratio scales have a true zero point, allowing meaningful ratio comparisons such as 'twice as much.'

Question 3

In a Gage R&R study, if reproducibility is very high relative to total variation, what is the most likely cause?

Accepted Answer

Different operators measure the same part differently

Answer

High reproducibility variation indicates operator-to-operator differences are contributing significantly to measurement variation.

Question 4

A control chart shows a run of 8 consecutive points on one side of the centerline. This is an example of:

Accepted Answer

A special cause signal

Answer

Eight or more consecutive points on the same side of the centerline is a standard Western Electric rule indicating a non-random special cause.

Question 5

What does kurtosis measure in a data distribution?

Accepted Answer

The peakedness and tail heaviness of the distribution

Answer

Kurtosis measures how peaked or flat a distribution is relative to a normal distribution, and the weight of its tails.

Lean Six Sigma Green Belt Certification Practice Test