What are statistical non-detects and how should they be treated in environmental data analyses?

• A. Values reported as below detection or quantitation limits and can be treated via substitution (LOD/2), maximum likelihood, regression on censored data, or specialized software.
• B. They are random outliers that should be discarded.
• C. They are data entries that should be replaced with the mean.
• D. They indicate a need to rerun the entire sampling program.

Answer: (A)