Q11 - Scientist: To study the comparative

[maryadkins]

The scientist tells us that in this study, a bunch of people with AF were divided into two groups: M and N.

They got different meds.

The only people who got better were the people given M.

That means what? That no one in the N group got better. In other words:

Cured --> M

~M --> ~Cured

What it DOESN'T mean is that we know if any people in the M group were NOT cured. There could be people in the M group who were not cured, sure. But among them there was at least one guy who got cured, while there wasn't the N group. So the reporter is wrong about that.

(D) brings in a different flaw that doesn't apply here: that there are people who got cured who didn't take either medicine. But the reporter doesn't do this. She qualifies her statement: "if anyone IN THE STUDY..." Everyone in the study got meds.

(A) correctly states the above.

(B) is wrong for the same reason (D) is: the reporter is NOT drawing a conclusion about the population as a whole.

(C) is just off. Nope.

(E) brings in this whole hypothetical that we don't need and doesn't get at the root of the issue, which is the logical flaw described above.


#officialexplanation

[irini101]

I narrow down to A and E then choose A as it points out the reporter's conditional reasoning flaw by simple language. But after the test I check back and find E conveys the same meaning as A but in convoluted language, now I am confused what's the flaw of E?

I diagram the stimulus as follows:

scientist: no M--> no cure, cure--> M
reporter: M--> cure

so I prephrase the flaw is conditional reasoning reversal: the reporter ignores that M alone may not be sufficient to cure
(M--> not cure)

A. definitely correct: the reporter reversed the conditional reasoning
E. the reporter ignores the possiblity: cure--> not M, M--> not cure--I think it points out the flaw in a convoluted way, but why E incorrect?

Did I mistaken or miss something? Could anyone help?

Thanks in advance!

[rzaman]

I'd love to know the answer to irini101's question as well. I get that the scientist says C-->M (c= cured, M=medication M) and the reporter incorrectly deduces ~C--> ~M or M-->C, making an incorrect necessary to sufficient swap there but isn't that a flaw that answer choice E points out as well? Is E wrong because the reporter doesn't really presume it but states it? That's the only thing I could get out of it but it feels like I'm making stuff up..

[zainrizvi]

(E) goes against the premises. The scientist says that the only people whose athlete's foot was cured had been given medication M.

C --> M
By contrapositive,
~M --> ~C

(E), if assumed, would say that there is a subgroup that is cured only if there is no medication

C --> ~M
By contrapositive,
M --> ~C

That goes against the scientists premises, so it is not a flaw in the reporters reasoning.

[dhlim3]

Why is D wrong?

Scientist: Cured -> M
Reporter: M -> Cured (contrapositive of ~Cured -> ~M, a mistaken negation)

So it's the classic"A-> B, therefore, if B then A" mistaken reversal flaw.

One way to translate this in English is "fails to consider that the absence of sufficient condition could still lead to necessary condition."


To illustrate:

If you exercise, you are healthy.

Mistaken Negation: If you don't exercise, you are not healthy
Mistaken Reversal: You are healthy, therefore you exercise.

They are essentially identical flaws (fails to allow for the possibility that you can still be healthy without exercising OR takes for granted that exercising is the only way to be healthy.)



I thought D reflected this exact flaw ("Fails to allow for the possibility that athlete's foot may be cured [necessary condition] without any of the two medications [sufficient condition]).

Help.

[lsat2016]

Could anyone explain why D is wrong??

[karamcdono]

^^ had the same problem with (D) as these two. Can someone please help?!

[keonheecho]

The scientist tells us that in this study, a bunch of people with AF were divided into two groups: M and N.

They got different meds.

The only people who got better were the people given M.

That means what? That no one in the N group got better. In other words:

Cured --> M

~M --> ~Cured

What it DOESN'T mean is that we know if any people in the M group were NOT cured. There could be people in the M group who were not cured, sure. But among them there was at least one guy who got cured, while there wasn't the N group. So the reporter is wrong about that.

(D) brings in a different flaw that doesn't apply here: that there are people who got cured who didn't take either medicine. But the reporter doesn't do this. She qualifies her statement: "if anyone IN THE STUDY..." Everyone in the study got meds.

(A) correctly states the above.

(B) is wrong for the same reason (D) is: the reporter is NOT drawing a conclusion about the population as a whole.

(C) is just off. Nope.

(E) brings in this whole hypothetical that we don't need and doesn't get at the root of the issue, which is the logical flaw described above.

Hi,
I'm still unsure about (A). The reporter says that if a person received medication A, then athletes foot was cured, but that doesn't imply causation, does it? And the scientist never says there is causation either. But (A) says that the reporter concludes from evidence showing only that M can cure athlete's foot that M always cures athletes foot. But that's not what the reporter is saying, is it?

Thank you

[keonheecho]

Ohhhhhh I think I see why E is wrong....is (E) also wrong because the reporter does not presume this, he actually assumes it to be false?

The statement basically seems to say that he assumes that for some people, cured--> ~M, which would be contraposed to M--> ~cured, which is the opposite of what the reporter is trying to say....Is this valid reasoning?


Thank you

[maryadkins]

(E) is a mess, and it's confusing. It's the assumption of a negation of a conditional. Ready to eliminate it and move on now?

It's saying that the reporter presumes that a conditional is NOT true. That conditional is:

Group of people who are cured --> Do not take M

Contraposed:

Do take M --> Not cured

He's assuming, according to (E), that this is NOT true. So we'd have to negate the conditional, which you do simply by making the "necessary" half of the statement not necessary:

Group of people who are cured who DO maybe take M.

Or:

If those people do take M, they may be cured.

But this isn't an assumption. Because we already know that M can cure it; the scientist told us so.

I'm still unsure about (A). The reporter says that if a person received medication A, then athletes foot was cured, but that doesn't imply causation, does it? And the scientist never says there is causation either. But (A) says that the reporter concludes from evidence showing only that M can cure athlete's foot that M always cures athletes foot. But that's not what the reporter is saying, is it?

Causation versus correlation isn't the issue here. We know M cures it, the scientist said so, and the reasoning flaw is in assuming that just because it can cure it, it always does (i.e. (A)).

[ganbayou]

Why do you have to add "maybe" when you negate the conditional statement?