CLS Research Methods & Evidence-Based Practice 2 — Questions and Answers
Question 1: In a controlled lubrication experiment, what is the purpose of a 'blind' evaluation protocol?
- To reduce equipment costs
- To eliminate evaluator bias when assessing lubricant performance (Correct answer)
- To simplify data collection procedures
- To increase the number of test replicates
Correct answer: To eliminate evaluator bias when assessing lubricant performance
A blind evaluation protocol prevents evaluator bias by concealing which lubricant sample is being tested.
Question 2: Which statistical measure best describes the spread of tribological test data around the mean?
- Median
- Mode
- Standard deviation (Correct answer)
- Arithmetic mean
Correct answer: Standard deviation
Standard deviation quantifies the dispersion of data points around the mean, indicating test repeatability.
Question 3: What does a peer-reviewed journal article provide that a manufacturer's product bulletin typically does not?
- Viscosity grade information
- Independent expert scrutiny of methodology and results (Correct answer)
- Application recommendations
- Product pricing data
Correct answer: Independent expert scrutiny of methodology and results
Peer review subjects research to independent expert evaluation of methodology, data, and conclusions before publication.
Question 4: When interpreting oil analysis trend data, which approach aligns best with evidence-based lubrication practice?
- Acting on a single outlier data point immediately
- Establishing baselines and tracking changes over multiple samples (Correct answer)
- Using only the most recent sample result
- Relying solely on lubricant supplier recommendations
Correct answer: Establishing baselines and tracking changes over multiple samples
Trend analysis over multiple samples provides statistically meaningful evidence compared to reacting to single-point data.
Question 5: A lubrication engineer wants to compare two greases for bearing life. Which experimental design is most rigorous?
- Testing one grease, then the other sequentially on the same equipment
- Randomized comparative testing with matched test units and controls (Correct answer)
- Using manufacturer-supplied test data only
- Testing under a single load and speed condition
Correct answer: Randomized comparative testing with matched test units and controls
Randomized comparative testing with controls minimizes confounding variables and produces reliable comparative data.
Question 6: In the context of CLS research, what is a 'null hypothesis'?
- A hypothesis with no practical application
- A baseline assumption that there is no significant difference between tested conditions (Correct answer)
- A hypothesis that has already been disproven
- A statement describing the expected test outcome
Correct answer: A baseline assumption that there is no significant difference between tested conditions
A null hypothesis assumes no significant effect or difference exists, and statistical testing either rejects or fails to reject it.
Question 7: Which ASTM standard specifically governs the repeatability and reproducibility (R&R) requirements for lubricant test methods?
- ASTM D4057
- ASTM D3244 precision statements (Correct answer)
- ASTM D2272
- ASTM D5185
Correct answer: ASTM D3244 precision statements
ASTM D3244 provides guidelines for utilizing precision data in developing acceptable test method results including R&R statements.
CLS Research Methods & Evidence-Based Practice 2
In a controlled lubrication experiment, what is the purpose of a 'blind' evaluation protocol?