LSAT Weaken Practice Question: Biased Sample
An original weaken question from our free Question of the Day rotation, built around a trap the LSAT reuses constantly: biased sample. Try it first, then read the explanation — it teaches the move, not just the answer.
Your job:Make the conclusion less believable.
Trellis & Trowel, a magazine devoted to raised-bed gardening techniques, recently surveyed its subscribers. Eighty-two percent of respondents reported that raised beds produce healthier vegetables than in-ground plots do. The magazine's editor concluded that most home gardeners nationwide find raised beds superior.
Which one of the following, if true, most seriously undermines the editor's conclusion?
Show the answer & full explanation
The correct answer is D
The JBDM line
Just because most of this magazine's subscribers prefer raised beds doesn't mean most home gardeners do.
The maybes
- MaybeMaybe people who already love raised beds are exactly who subscribes to a raised-bed magazine.
- MaybeMaybe gardeners without strong opinions never see the survey at all.
Why D is right
The sample is stacked. A raised-bed magazine's subscribers are raised-bed enthusiasts almost by definition, so their opinions can't stand in for gardeners nationwide. Point out the biased sample and the leap from 'our readers' to 'most home gardeners' snaps.
Why the others are wrong
- ACost is a different question — the conclusion is about which method gardeners find superior, not which is cheaper.
- BOnline versus mail changes the medium, not the fundamental bias of who was asked.
- CA few dual-method gardeners in the pool doesn't fix — or expose — the sampling problem.
- EA small sample isn't automatically a biased one; size isn't the flaw here.
Sammy's note
Ask who got surveyed before you ask what they said.
What's a JBDM line?
Just Because Doesn't Mean (JBDM) is the Burton Method's foundational framework for attacking LSAT arguments: identify the premise, identify the conclusion, then say "just because [premise] doesn't mean [conclusion]" and generate "maybes" — alternative explanations that expose the gap between them. That gap is what weaken, flaw, strengthen, and assumption questions all test, so every explanation on this page starts with the JBDM line. It's a micro-lesson in the system, not just an answer key.
One question a day builds the habit
Answer today's question and start a streak — then see how Sammy teaches the whole system, JBDM included, in a free lesson.