Logical Reasoning

PT109 · S4 · Q20 It would be wrong to conclude that

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It would be wrong to conclude that a person has a Streptococcus infection if there is no other evidence than the fact that Streptococcus bacilli are present in the person’s throat; after all, infection does not occur unless the host is physically run down.

Conclusion

If only evidence of Strep IF only evidence infection is presence of of X is Y Strep in throat, it would be wrong to THEN wrong to conclude Strep infection conclude X

Evidence

If not physically run down IF not Z then no Strep infection THEN not X then X doesn't occur

Evaluate / Goal

This argument is essentially saying

20.

The reasoning in which one of the following is most similar to the reasoning in the argument above?

When a person experiences blurred
Bad Premise Match
This does have the right type of conclusion: You can't conclude X (physical eye defect) on the basis of Y (blurred vision) So the correct premise would say, Because some other thing (Z) is also needed for X to be true. Instead, the premise says, Because some other thing (drugs) can also cause Y.
7% picked this
Correct
Even if a healthy lavender
Why this is right
This does have the right type of conclusion: You can't conclude X (plant will bloom) on the basis of Y (6+ hrs of sun) So the correct premise would say, Because some other thing (Z) is also needed for X (bloom) to be true. And, indeed, the premise says Because some other thing (alkaline soil) is also needed for bloom.
Skill tested: Parallel · how this choice captures the argument's function is the move to repeat next time.
53% picked this
When a bee colony fails
Bad Premise Match
This does have the right type of conclusion: You can't conclude X (low temps killed them) on the basis of Y (bee colony died) So the correct premise would say, Because some other thing (Z) is also needed for X to be true. Instead, the premise says, X isn't a plausible hypothesis. "Low temps wouldn't kill a colony because they have good defense mechanisms against extreme cold."
4% picked this
A female holly plant cannot
No Premise
This doesn't actually present an argument. It just presents one fact and then presents an unsupported claim that you can't infer a certain something from that fact. You can't conclude X (2+ males near a female will result in more berries than single male) on the basis of Y (females need a male nearby to make berries). There should now be a premise saying, Because some other thing (Z) is also needed for X to be true. But there's nothing else here.
2% picked this
A person cannot be presumed
Bad Premise Match
This does have the right type of conclusion: You can't conclude X (hypertensive) on the basis of a single Y (high BP reading for that person) So the correct premise would say, Because some other thing (Z) is also needed for X to be true. Instead, the premise says, A single Y doesn't qualify as X. It's only if you constantly have Y that we call it X. That's an inferior match compared to the correct answer. This doesn't bring in a third factor, it just complains about the frequency of the established factor. This would match the original, if the original had been more like, "You can't conclude Strep infection just because Strep is present. After all, being 10% present isn't enough for infection. It would have to be present almost everywhere to be infection."
34% picked this

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