Which statement best describes stratified random sampling's purpose?

• A. To focus only on the largest particles
• B. To ensure that samples include the full range of a construction process
• C. To sample only from the top layer
• D. To minimize the number of samples

Answer: (B)

Stratified random sampling aims to capture variability across the process by dividing the production into homogeneous groups (strata) and sampling randomly within each group. In asphalt plant practice, properties like temperature, binder content, aggregate gradation, and moisture can vary during a run, so you don’t want to sample from just one point or one batch. By taking samples from each stratum—different times, lots, or ranges of conditions—you ensure the overall results reflect the full range of operating conditions. This leads to a more accurate picture of the entire construction process.

It's not about focusing on the largest particles, sampling only from the top layer, or minimizing the number of samples.