Improve: Solutions & DOE
50 practice questions with explanations — 15 free to try
PassNova has 50 Lean Six Sigma Green Belt practice questions on Improve: Solutions & DOE, each with a clear explanation. A 15-question taster is free with no sign-up; the full bank is part of PassNova Premium. Updated for 2026.
Improve: Solutions & DOE: example questions & answers
3 worked examples with answers and explanations below. Try 15 Lean Six Sigma Green Belt questions free in the browser; the full 50-question Improve: Solutions & DOE bank is part of PassNova Premium.
A full factorial design investigates 3 factors, each at 2 levels, with no replication. How many experimental runs are required?
- A6
- B8✓
- C9
- D16
Answer: A two-level full factorial requires 2^k runs; with k = 3 factors this is 2^3 = 8 runs.
In a designed experiment, an 'interaction' between two factors means that:
- AThe two factors are statistically correlated before the experiment
- BThe effect of one factor on the response depends on the level of the other factor✓
- CBoth factors must be set to their high level to improve the response
- DThe factors can be analysed only one at a time
Answer: An interaction exists when the effect of one factor on the response changes depending on the setting of another factor, something one-factor-at-a-time testing cannot detect.
Why is randomization of run order important in a designed experiment?
- AIt reduces the total number of runs needed
- BIt helps prevent unknown lurking variables (such as time-related trends) from biasing the results✓
- CIt forces the response to follow a normal distribution
- DIt guarantees that all interactions are estimable
Answer: Randomizing run order spreads the influence of uncontrolled, time-dependent factors across the design so they do not systematically bias the estimated effects.