Logical Reasoning

PT150 · S3 · Q9 Marketing agent: A survey of my business

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Marketing agent: A survey of my business clients reveals that, of those who made a profit last year, 90 percent made at least $100,000 in profit for the year.

Conclusion

90% of my business clients increased their profits at least tenfold last year.

Evidence

Last year, 90% of my clients who made a profit made at least $100k in profit.

In prior years, not one of these businesses made an annual profit of more than $10k.

Evaluate

This argument would be correct if the conclusion had said,

The argument's only flaw is that in the Evidence it's talking about 90% of my profitable clients but then in the Conclusion it jumps to talking about 90% of my clients

Suppose this marketing agent has 20 clients. Last year 10 of them were profitable and 10 were not profitable.

The evidence says that 9 of those 10 profitable clients posted $100k in profits after having never done better than $10k.

So 90% of her profitable clients increased tenfold last year. But this is still just 9 out of 20 ... 45% of her clients.

Goal

Look for an answer complaining that the Evidence was about profitable clients whereas the Conclusion was about all clients.

9.

The reasoning in the marketing agent's argument is most vulnerable to criticism on the grounds that the argument

  1. overlooks the possibility that the

    Not an Objection

    Does it weaken the argument to say that the ones who eclipsed $100k barely surpassed that threshold? Nope. If their previous max was 10k, and now they are at least 100k, then it's mathematically correct to say they've increased their profits at least tenfold. (Math nerds -- you might have thought, they've only increased their profits 9x. $100k is 1000% of $10k, but it's only a 900% increase. But the usage of twofold / threefold is to mean a percentage of, not a percent increase, even though people say "increased twofold". In other words, if I used to make $8 / hr and now I make $16 / hr, we can say my new wage is 200% of my old one or my new wage is a 100% increase of my old one or my wage just increased twofold)

    3% picked this

  2. fails to explain why some

    Not an Objection

    Can we weaken this argument by saying, "Well how come that other 10% didn't increase their profits tenfold?" No. The author isn't saying that everyone she helps gets a tenfold increase. She successfully wins her argument if it's a true claim that 90% of her clients increased their profits tenfold last year.

    3% picked this

  3. Correct

    draws a conclusion about all

    Why this is right

    This speaks to the fact that the Evidence was about "Of those clients who are profitable, 90% did X", to a Conclusion that is saying "90% of my clients did X".

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

    83% picked this

  4. treats conditions that are sufficient

    Wrong Flaw

    This answer describes the famous Necessary vs. Sufficient flaw, in which an author presents a conditional logic premise but then applies the rule in an illegal backwards or opposite fashion. There was no conditional logic premise here, so this answer can't match.

    4% picked this

  5. overlooks the possibility that not

    Bad Objection: Too Weak

    Since this starts with "fails to consider / overlooks the possibility", we ask ourselves if it would weaken. Can we hurt the argument by saying, "Hey author, SOME of your clients made an annual profit of less than $10k last year!" No, the author would be happy to accept that. Her conclusion is only claiming that 90% of her clients increased profits at least tenfold. She can readily admit that some of her clients (up to 10% of them) didn't profit tenfold. They might have profited less than $10k. They might not have profited at all. She was never assuming or claiming that all of her clients had profits over $10k, just that 90% of them did.

    7% picked this

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