Which method is used when accuracy is important?

• A. Area monitoring.
• B. Grid.
• C. Boundary of contamination.
• D. Course Leg.

Answer: (B)

When accuracy is important, you want uniform coverage that lets you map exactly how a variable changes across an area. A grid sampling plan places sampling points at the intersections of evenly spaced lines, creating a regular network. This regular spacing provides consistent, repeatable data and makes it possible to interpolate values between points with known uncertainty. It also reduces spatial bias that can occur if you sample along irregular routes or only at obvious features.

Other approaches focus on broader checks or edges rather than full distribution. Monitoring the area can reveal whether contamination is present but might miss small hotspots if sampling isn’t systematic. Delineating the boundary of contamination targets the edges of the affected zone, not the inside distribution. Following a course leg samples along a single line or path, leaving large gaps between passes and potentially missing variation off the path.

So, for precise, statistically reliable information about the entire area, the grid approach is the best choice.