Logical ReasoningDifficulty: Hard

PT118 S4 Q20 Explanation

Polling data reveal that an overwhelming

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsParallel Flaw

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Stimulus

Polling data reveal that an overwhelming majority of nine-year-olds can correctly identify the logos of major cigarette brands. However, of those nine-year-olds who recognize such logos, less than 1 percent smoke. Therefore, there is of cigarette brand logos and smoking.

What this question is testing

Parallel Flaw

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
20.

Which one of the following uses flawed reasoning most similar to the

Answer choices

  1. Correct38% picked this

    The concern about the long-term effect on dolphins of small quantities of mercury in the ocean is unfounded. During a three-month observation period, 1,000

    Why this is right

    This gets at the same Sampling objection of, "Whoa — you're looking at too narrow a slice of time, there, buddy." The conclusion is trying to gauge the long-term effect on dolphins, but we're only looking at a 3 month sample. Maybe mercury hasn't done anything bad to them yet, but if we check back in a couple years we'll see it has done something bad.

    Skill tested: Parallel Flaw · how this choice captures the argument's function is the move to repeat next time.

  2. Bad Objection Match1% picked this

    Many ten-year-olds dream of becoming actors. Yet it is not likely they will seriously consider becoming actors, because most parents discourage their children from

    What would be our objection to this argument? - whether a parent discourages a kid doesn't change whether the kid will seriously consider their dream - maybe the "most parents" who discourage competitive career choices doesn't overlap with the "many 10 year old's" who have acting dreams. Neither of those matches well with: "maybe not yet, but eventually it could happen" or "maybe not for these people, but possible for some other group of people"

  3. Bad Objection Match3% picked this

    Most dentists recommend using fluoride to reduce the incidence of cavities, but few recommend giving up candy entirely; so, using fluoride is probably more

    What would be our objection to this argument? - maybe dentists recommend fluoride, not because it's more effective than giving up sweets but because they are realistic that people will not adopt the suggestion to give up sweets. This objection of "maybe that's not happening because of X, but because of Y" doesn't match up well with our objections to the original argument: "maybe not yet, but eventually it could happen" "maybe not for these people, but possible for some other group of people"

  4. Bad Objection Match53% picked this

    A large percentage of men exercise moderately throughout their lives, but the average life span of those who do so is not significantly greater

    What would be our objection to this argument? - the argument switches from talking about "average life span" in the evidence to talking about "good health" in the conclusion. This objection of "maybe exercise is correlated with good health, just not correlated with longer life span" doesn't match up well. "maybe not yet, but eventually it could happen" "maybe not for these people, but possible for some other group of people"

  5. Bad Objection Match5% picked this

    Most people cannot name their legislative representatives. Nonetheless, this is insignificant, for when queried, most of them displayed an adequate

    What would be our objection to this argument? - just because they have an adequate command of current issues doesn't mean it's fine that they can't name their reps. - maybe it's important to be able to name your reps so that if your rep was in the news for behavior you objected to, you would know (and thus be an informed voter when deciding whether to re-elect that rep). Our objection seems to be something like, "Just because they have this ability doesn't mean it isn't bad that they lack this other ability". Doesn't match either of our objections to the original argument: "maybe not yet, but eventually it could happen" "maybe not for these people, but possible for some other group of people"

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