10 free, exam-style Certified Six Sigma Green Belt (CSSGB) (CSSGB) practice questions with answers and
explanations. No signup required. Work through them below, then take the
full free CSSGB practice test to study every exam domain.
These 10 free CSSGB questions are organized by exam domain, so you can see how each part of the Certified Six Sigma Green Belt (CSSGB) blueprint is tested. Reveal the answer and explanation under each question.
Domain 1: Six Sigma and the Organization (and Lean & DFSS Fundamentals)
Question 1
A failure mode has S=3, O=2, D=2 (RPN=12) and another has S=9, O=1, D=2 (RPN=18). A team member argues the first mode should be prioritized since it has a lower RPN. This reasoning is:
- Correct - lower RPN always means lower priority
- Incorrect - the second mode's high severity (safety impact) warrants attention despite a slightly higher RPN
- Correct - RPN is the only factor that matters
- Incorrect - occurrence is the most important factor
Show answer & explanation
Correct answer: B - Incorrect - the second mode's high severity (safety impact) warrants attention despite a slightly higher RPN
Domain 2: Define Phase
Question 2
A hotel receives complaints about slow check-in. The front desk manager knows the root cause is an outdated software system. Which approach is MOST appropriate?
- DMAIC
- DMADV
- Just Do It - implement the known solution
- Root cause analysis
Show answer & explanation
Correct answer: C - Just Do It - implement the known solution
Question 3
A three-step process has yields of 97%, 95%, and 98%. The Rolled Throughput Yield (RTY) is:
- 96.7%
- 95.0%
- 90.3%
- 97.0%
Show answer & explanation
Correct answer: C - 90.3%
Domain 3: Measure Phase
Question 4
A process has Cp = 1.5 and Cpk = 0.8. What does this indicate?
- The process has good spread and is well-centered
- The process has adequate spread (Cp) but is off-center (Cpk < Cp)
- The process is incapable
- The measurement system is inadequate
Show answer & explanation
Correct answer: B - The process has adequate spread (Cp) but is off-center (Cpk < Cp)
Question 5
USL = 60, LSL = 40, μ = 52, σ_within = 3. What is Cpk?
- 0.89
- 1.11
- 1.33
- 1.00
Show answer & explanation
Correct answer: A - 0.89
Domain 4: Analyze Phase
Question 6
A fire alarm goes off but there is no fire. This is analogous to a:
- Type II error
- Type I error (false alarm/false positive)
- Correct decision
- Power calculation
Show answer & explanation
Correct answer: B - Type I error (false alarm/false positive)
Question 7
A machine stops. Why? The fuse blew. Why? It was overloaded. Why? The bearing was not lubricated. Why? The lubrication pump failed. Why? The pump shaft was worn. The root cause is:
- The fuse blew
- The machine was overloaded
- The bearing was not lubricated
- The pump shaft was worn - leading to a maintenance action
Show answer & explanation
Correct answer: D - The pump shaft was worn - leading to a maintenance action
Domain 5: Improve Phase
Question 8
A changeover currently takes 90 minutes. After SMED analysis, 30 minutes of tasks are converted to external setup and the remaining tasks are streamlined by 50%. The new changeover time is approximately:
- 30 minutes
- 45 minutes
- 60 minutes
- 15 minutes
Show answer & explanation
Correct answer: A - 30 minutes
Domain 6: Control Phase
Question 9
An operator adjusts a machine every time the last reading is above the target, even though the process is stable. This is an example of:
- Appropriate use of control chart signals to maintain process centering
- Tampering - overreacting to common cause variation
- Proactive adjustment based on predicted trends in the process data
- Following the corrective action procedure defined in the control plan
Show answer & explanation
Correct answer: B - Tampering - overreacting to common cause variation
Question 10
A process can be in statistical control but still produce defective output if:
- The control limits and specification limits are not properly aligned with each other
- The process variation (voice of the process) exceeds the specification limits (voice of the customer)
- The control chart is incorrectly constructed
- The sample size is too small
Show answer & explanation
Correct answer: B - The process variation (voice of the process) exceeds the specification limits (voice of the customer)