Under FRE 701, lay opinions are admissible if:

• A. They are based on scientific data and require expert testimony.
• B. They are based on the witness’s perception and help explain testimony in a non-technical way.
• C. They are based on the witness's personal knowledge of the scientific method.
• D. They are about legal conclusions.

Answer: (B)

Lay opinions under FRE 701 are admissible when they come from the witness’s own perceptions and help the jury understand the testimony or determine a fact in issue, as long as they don’t rely on specialized knowledge. This is why the best choice says the opinion is based on what the witness perceived and presented in a non-technical way to clarify the testimony. The rule allows everyday impressions—like noticing someone’s behavior, estimating speed, or describing a scene—so long as it helps, not replaces, the jurors’ own evaluation.

Other options miss the mechanism: relying on scientific data or the scientific method goes beyond a layperson’s basis and falls under expert testimony. Framing an opinion as a determination of a legal conclusion asks the witness to decide issues of law, which the judge should determine.