Which sampling approach provides a better composite representation?

• A. Larger sample collected less often
• B. Smaller sample collected more often
• C. Smaller sample collected less often
• D. Larger sample collected more often

Answer: (B)

Composite sampling aims to reflect the average conditions over a period by pooling several smaller portions taken through that interval. The accuracy of that representation hinges on capturing the variability that occurs during the measurement window. Taking smaller samples more often creates a time series that records changes in flow, dilution, and pollutant loads as they happen. When you combine those frequent, small samples, the resulting composite better mirrors the actual conditions over the period. In contrast, one large sample collected infrequently tends to average out peaks and dips, missing important fluctuations and giving a less accurate picture of the period’s characteristics. For that reason, smaller samples collected more often provide the best composite representation.