Logical Reasoning · Flaw

PrepTest 133 · Section 2 · 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

An average tells you how much each one gets, not how much is spent in total, so it can't by itself show which thing gets more overall support.

The basic logic

The argument compares the average amount per person in two groups and concludes that one group's whole area is valued more. Look for the gap between 'per person' and 'in total': a group with a lower average but many more members could get far more overall. A cousin of Percent vs. Number.

Tiny words that decide it

“average”
“per person”
“total”

Playground logic

Tommy's patty: the average cat toy costs less than the average dog toy. His top bun: the family loves Biscuit more than Mr. Whiskers. The missing piece: he never checked how many toys each pet gets, so the total could easily favor the cat.

Step 2 · The kid story

Who Gets the Fancier Toys?

Tommy dumped the pet toy bin onto the rug. "Look," he announced, hiding a candy bar behind his back. "The average dog toy for Biscuit costs eight dollars. The average cat toy for Mr. Whiskers costs two dollars. Clearly this family loves Biscuit more!" Mr. Whiskers stared at him. Lulu flipped open her clipboard. "Biscuit has three toys. Mr. Whiskers has forty-two." She did the math. "That's twenty-four dollars on Biscuit and eighty-four dollars on Mr. Whiskers." Tommy's mouth fell open. "So the cheap toys add up to way more?" "An average tells you about one toy," said Lulu. "It doesn't tell you the whole pile." Biscuit, chewing one of his three toys, did not seem to mind.

Step 3 · Try the model question

Tommy: The average toy we buy for Biscuit costs more than the average toy we buy for Mr. Whiskers. Obviously, our family cares more about Biscuit than about Mr. Whiskers.

Tommy's reasoning is weak because he

Step 4 · The courtroom tale

The Parade Float Fuss

A marching band leader sued the parade committee. "The committee cares more about floats than bands!" she declared. "The average float gets a bigger budget than the average band." Mr. Whitfield rose and adjusted his suspenders. "Your Honor, how many floats are in the parade?" "Three," said the clerk. "And bands?" "Forty." Mr. Whitfield smiled. "So the committee spends far more on bands as a group, even if each band gets a little less. An average describes one slice, not the whole pie." The judge closed the folder. "The average alone cannot tell us what the committee values most. Case dismissed."

Step 5 · Work the real question

Open PrepTest 133, Section 2, Question 4 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Identify the evidence: an average per person in two groups. Identify the conclusion: one whole area is valued more than the other. Ask whether an average can show overall commitment. The answer you want points out that the overall amount could tell a very different story than the per-person figures. Eliminate choices that pin assumptions on the argument it never makes or that name a gap the conclusion doesn't depend on.