Logical Reasoning · Flaw

PrepTest 110 · Section 3 · Question 4

Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.

Step 1 · Pre-Question Guidance · read this first

Question type

Flaw

The one idea it tests

A sample from one small place is used to speak for a much bigger group.

The basic logic

Compare where the evidence came from with who the conclusion is about. If the sample is from one local corner and the conclusion covers the whole country, ask whether that corner is typical. That gap is the Weird Sample.

Tiny words that decide it

“shows”
“most”
“every”
“sample”

Playground logic

Owen surveys dog owners at one park in one town, then makes a claim about every dog owner in the country. His patty is one local crowd; his top bun is the whole nation. That is a Weird Sample, even if he picked people fairly within the park.

Step 2 · The kid story

Owen's Great Dog Walk Survey

Owen stood at the gate of Maple Park with a clipboard he borrowed from Lulu. He asked fifty dog owners, chosen by drawing names from a hat, "Do you plan to walk your dog every day?" Forty-six said yes. Owen marched to school. "Ninety percent! Almost every dog owner in the whole country wants daily walks. So if dogs are out of shape nationwide, it's not because owners don't want to walk them." Priya tilted her head. "Where is Maple Park?" "Right next to the big hiking trail," Owen said. Priya smiled. "So you asked people who chose to live by a trail. Fair draw, but from one very special spot." Biscuit, who had not been walked that day, sighed loudly.

Step 3 · Try the model question

Fifty dog owners at one park in our town were chosen at random and asked whether they planned to walk their dogs every day. Over ninety percent said yes, which proves that nearly all dog owners in the country want to walk their dogs daily, so if dogs nationwide are out of shape, the cause cannot be owners' lack of desire.

The reasoning above is most open to criticism on which ground?

Step 4 · The courtroom tale

The Case of the Seaside Sunscreen

A sunscreen maker was on trial for advertising that "nearly every family in the nation uses sunscreen daily." Its lawyer proudly showed the evidence: a fair, random survey of two hundred families. Mr. Whitfield stood. "Where were these families surveyed?" The lawyer coughed. "At a beach resort in July." Mr. Whitfield snapped his suspenders. "Your Honor, the draw may be fair, but the pond is special. Families at a summer beach are hardly typical of families in snowy towns in January." The judge nodded. "A random pick from one unusual place still speaks only for that place. The ad overreaches." The sunscreen maker quietly added the words "at our beach."

Step 5 · Work the real question

Open PrepTest 110, Section 3, Question 4 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Locate the sample: who was asked, and from where. Then locate the conclusion: who it claims to describe. If the conclusion's group is much wider than the sample's place, ask whether the sample is typical. Random selection inside a small place does not fix a sample that comes from only that place. Choose the answer that names this mismatch between sample and target group, and skip choices about side details.