Which of the following is NOT a characteristic of a composite sample?

The correct answer highlights an important aspect of composite sampling methodology. A composite sample is designed to represent a comprehensive view of water quality over a specified period or under varying conditions. It achieves this by combining multiple grab samples, which are taken at different times or locations. This process allows for a more representative average of water quality than a single grab sample.

Immediate analysis after collection is not a requirement for composite samples. Due to its design, where samples are aggregated from various points or times, the analysis can often be conducted at a later time, provided that the samples are preserved correctly and stored under conditions that prevent degradation. This flexibility allows for more efficient testing schedules and ensures that the composite sample accurately reflects the overall conditions during the sampling period.

In sum, the nature of composite sampling allows for some delay in analysis, distinguishing it from the general expectation of other types of samples that may require immediate attention.