PIC Quality Acceptance Sampling 2 — Questions and Answers
Question 1: What is the primary purpose of a Lot in quality acceptance sampling for asphalt paving?
- To group material for statistical evaluation of uniformity (Correct answer)
- To identify the contractor's delivery schedule
- To separate materials by truck number
- To record the daily paving crew size
Correct answer: To group material for statistical evaluation of uniformity
A Lot is a defined quantity of material grouped together so that statistical sampling can evaluate whether the entire production meets specification.
Question 2: When a sublot sample fails a test, which action is most appropriate before rejecting the entire lot?
- Increase the number of sublot samples and retest (Correct answer)
- Immediately stop paving and remove all placed material
- Accept the material at full pay
- Reduce the compaction roller passes
Correct answer: Increase the number of sublot samples and retest
Increasing sampling frequency and retesting gives a statistically more reliable picture before a full lot rejection decision is made.
Question 3: Which statistical term describes the spread of individual test results around the mean in acceptance sampling?
- Standard deviation (Correct answer)
- Moving average
- Pay factor
- Confidence interval
Correct answer: Standard deviation
Standard deviation quantifies how much individual measurements vary from the mean, directly affecting quality index calculations.
Question 4: A pavement inspector receives a mix with an asphalt binder content of 5.8% against a job mix formula target of 5.4% ± 0.3%. What is the correct assessment?
- The mix is out of specification and should be flagged for rejection (Correct answer)
- The mix is within tolerance and should be accepted
- The mix should be tested again with a different method
- The binder content is irrelevant if density passes
Correct answer: The mix is out of specification and should be flagged for rejection
5.8% exceeds the upper tolerance limit of 5.7% (5.4 + 0.3), so the material falls outside specification.
Question 5: In stratified random sampling, the pavement area is divided into segments primarily to:
- Ensure samples represent the entire lot uniformly (Correct answer)
- Reduce the number of required tests
- Simplify logistics for the testing lab
- Match the contractor's production schedule
Correct answer: Ensure samples represent the entire lot uniformly
Stratification ensures every section of the lot has an equal chance of being sampled, preventing bias toward one part of the job.
Question 6: What does a pay factor greater than 1.00 (100%) typically indicate in a performance-related specification?
- The material quality exceeded specification requirements, earning a bonus (Correct answer)
- The contractor will be penalized for poor workmanship
- The lot must be removed and replaced
- The test was invalid and must be repeated
Correct answer: The material quality exceeded specification requirements, earning a bonus
Pay factors above 1.00 represent incentive payments awarded when quality characteristics exceed the minimum specification thresholds.
Question 7: Which of the following best defines 'acceptance quality limit' (AQL) in pavement sampling?
- The maximum percent defective considered acceptable for a lot (Correct answer)
- The minimum number of cores required per day
- The target air void content from the job mix formula
- The compaction roller pattern required by the inspector
Correct answer: The maximum percent defective considered acceptable for a lot
AQL defines the threshold of defective material that can be tolerated while still accepting the lot at full or reduced payment.
PIC Quality Acceptance Sampling 2
What is the primary purpose of a Lot in quality acceptance sampling for asphalt paving?