Lean Six Sigma Green Belt Certification Basic Statistical Tools 4

Question 1

When constructing a histogram, the recommended number of bins for a dataset of 64 observations using the square-root rule is approximately:

Accepted Answer

8

Answer

The square-root rule recommends √n bins; √64 = 8 bins.

Question 2

In regression analysis, an R² value of 0.85 means:

Accepted Answer

85% of the variation in Y is explained by the model

Answer

R² (coefficient of determination) represents the proportion of variation in the response variable explained by the predictor(s).

Question 3

A process average is 100 units with σ = 4. The upper specification limit is 112. What is the Cpu?

Accepted Answer

1.00

Answer

Cpu = (USL − mean) / 3σ = (112 − 100) / (3 × 4) = 12 / 12 = 1.00.

Question 4

What is the primary purpose of a run chart in Six Sigma?

Accepted Answer

To monitor a process over time and detect trends or shifts

Answer

A run chart plots data in time sequence to reveal trends, cycles, or shifts in a process over time.

Question 5

Which level of measurement allows calculation of ratios and has a true zero point?

Accepted Answer

Ratio

Answer

Ratio scale has a true zero point, making ratios meaningful (e.g., 20 kg is twice 10 kg).

Lean Six Sigma Green Belt Certification Practice Test