A composite sample consists of what type of samples?

A composite sample is created by combining multiple individual samples collected at different times or locations into a single sample. The primary purpose of this method is to obtain an average representation of a larger group or area, thereby enhancing the reliability of the test results. This is particularly useful for evaluating water quality or contamination levels over time.

Grab samples are a fundamental component in creating a composite sample, as they represent discrete measurements taken from a specific location or instance. By taking grab samples at various times or from different locations and then combining them, one can capture variations in conditions or concentrations, which can lead to a more accurate assessment of the overall situation.

In contrast, random samples refer to the method of selecting samples where each has an equal chance of being chosen, which can lead to less systematic sampling across time or space. Bulk samples tend to involve larger volumes of material collected from a single source rather than a series of distinct, smaller samples. Continuous samples are taken over a set period without interruption, capturing ongoing changes but not necessarily designed for mixing like composite samples are.