Q19 - The recent concert

[yihanqin]

Hi! Would someone please explain to me why C is the right answer? I chose B

Now that I'm looking at it , I'm guessing it's because Professor Willis, playing the expert in the pattern, should be introducing the conditional statement(if sample is labeled correctly, then it would contain organic compounds) instead of just stating a fact (the sample probably didn't contain any organic compounds).

Is this the reason? This is so tricky because I only focused on getting the conditional relationship right when I did this question.

[ohthatpatrick]

Thanks for bringing this one to the forum. Let's put up a full explanation.

Question Type: Match the Reasoning

Argument Core:

conclusion
Concert probably not properly promoted

why?

evidence
The concert didn't sell out.
and
Wells, a respected expert, said, "If doesn't sell out, not properly promoted."

MAKE IT MORE ABSTRACT
For our evidence, we need
- an expert who says "A --> B"
- a fact that says A happened

For our conclusion, we need
- B happened

(A) expert says "highly skilled -> probably survive"
a fact says "did not survive". Hmm, that's using the contrapositive.
Okay, do we conclude "NOT highly skilled"?
We do not.

(B) expert says something ... not conditional .... "probably"? Defer.

(C) expert says "properly repaired -> damage not noticeable"
fact says "damage IS noticeable". Okay, using contrapositive.
Do we conclude "NOT properly repaired"?
We do. Keep it.

(D) Not sure builder is expert, but expert says "No storm damage -> no repair for years"
Fact says "roof leaking". Is that storm damage? Feels loose. Defer.

(E) Expert says "properly conducted -> find lead in soil".
Fact says, "didn't find lead", so we should be concluding "not properly conducted".
Wait, what? This is concluding PROPERLY conducted? Eliminate.

(C) is the correct answer.

[yihanqin]

Thanks for bringing this one to the forum. Let's put up a full explanation.

Question Type: Match the Reasoning

Argument Core:

conclusion
Concert probably not properly promoted

why?

evidence
The concert didn't sell out.
and
Wells, a respected expert, said, "If doesn't sell out, not properly promoted."

MAKE IT MORE ABSTRACT
For our evidence, we need
- an expert who says "A --> B"
- a fact that says A happened

For our conclusion, we need
- B happened

(A) expert says "highly skilled -> probably survive"
a fact says "did not survive". Hmm, that's using the contrapositive.
Okay, do we conclude "NOT highly skilled"?
We do not.

(B) expert says something ... not conditional .... "probably"? Defer.

(C) expert says "properly repaired -> damage not noticeable"
fact says "damage IS noticeable". Okay, using contrapositive.
Do we conclude "NOT properly repaired"?
We do. Keep it.

(D) Not sure builder is expert, but expert says "No storm damage -> no repair for years"
Fact says "roof leaking". Is that storm damage? Feels loose. Defer.

(E) Expert says "properly conducted -> find lead in soil".
Fact says, "didn't find lead", so we should be concluding "not properly conducted".
Wait, what? This is concluding PROPERLY conducted? Eliminate.

(C) is the correct answer.

Thank you for the detailed explanation!

[jasonleb1]

I usually don't have trouble with parallel questions but this one has me stumped.

The stimulus says that the concert would sell out unless it was poorly promoted (not properly promoted) :

notSell Out--> notProperly Promoted i.e. notA --> notB

The rest of the stimulus gives us notSell Out -> notProperly Promoted i.e. notA --> notB.

The contrapositives of both of these would be B --> A, not A --> B.

So we're looking for a B --> A, therefore B --> A argument.

Answer choice C gives us:

Properly repaired --> notNoticeable i.e. A --> notB

Noticeable --> notProperly Repaired i.e. B --> notA

While a valid contrapositive, this doesn't match out B --> A argument in the stim so I eliminated it.

Obviously, I did something wrong, can someone please explain what it was?

[ohthatpatrick]

I think you're getting too granular and thinking that we care whether something is the "original" or the "contrapositive".

When you translate a sentence into a conditional statement, the designation of which idea is A vs. ~A is totally arbitrary.

You're symbolizing the "unless" conditional in the stim as
"If not sell out (notA), then not properly promoted (notB)"
But someone else could have equivalently written
"If properly promoted (A), then not sell out (notB)."

Those are both right. There's no "better" or "primary" way to write a conditional vs. its contrapositive. The term contrapositive has no meaning on its own; it's just in relation to however you chose to write the original conditional.

Similarly, you may have heard people speak of "Illegal Negations" and "Illegal Reversals". Those are one thing, not two things ... just as the conditional and its contrapositive are one thing, not two things.

A -> B = ~B -> ~A

B -> A = ~A -> ~B

The logical ingredients for this argument are basically:
1. an expert who gives us a conditional statement
2. a statement of fact that triggers the conditional statement
3. a conclusion that says the consequence of the conditional is probably true

We can make the stim and (C) the same by just choosing how we name our symbols so that they DO have a match.


(C) looks like
according to expert, "If prop repair (X), not notice damage (Y)"
statement of fact ... not-y "You CAN still notice damage"
probable fact ... thus, probably not-x "probably not proper repair"

Here's how the original stim lives up to same structure:
P1: according to an expert:"If X then Y" .. "if properly promoted, would sell out"
P2: a statement of fact .. not-Y "but it did NOT sell out"
Conc: probably not-X "probably not properly promoted"

Hope this helps.

[783874728]

I think you're getting too granular and thinking that we care whether something is the "original" or the "contrapositive".

When you translate a sentence into a conditional statement, the designation of which idea is A vs. ~A is totally arbitrary.

You're symbolizing the "unless" conditional in the stim as
"If not sell out (notA), then not properly promoted (notB)"
But someone else could have equivalently written
"If properly promoted (A), then not sell out (notB)."

Those are both right. There's no "better" or "primary" way to write a conditional vs. its contrapositive. The term contrapositive has no meaning on its own; it's just in relation to however you chose to write the original conditional.

Similarly, you may have heard people speak of "Illegal Negations" and "Illegal Reversals". Those are one thing, not two things ... just as the conditional and its contrapositive are one thing, not two things.

A -> B = ~B -> ~A

B -> A = ~A -> ~B

The logical ingredients for this argument are basically:
1. an expert who gives us a conditional statement
2. a statement of fact that triggers the conditional statement
3. a conclusion that says the consequence of the conditional is probably true

We can make the stim and (C) the same by just choosing how we name our symbols so that they DO have a match.


(C) looks like
according to expert, "If prop repair (X), not notice damage (Y)"
statement of fact ... not-y "You CAN still notice damage"
probable fact ... thus, probably not-x "probably not proper repair"

Here's how the original stim lives up to same structure:
P1: according to an expert:"If X then Y" .. "if properly promoted, would sell out"
P2: a statement of fact .. not-Y "but it did NOT sell out"
Conc: probably not-X "probably not properly promoted"

Hope this helps.

so the contrapositive can be chose as well? I guess that's why I eliminate this choice

[AnnaC286]

Thanks for bringing this one to the forum. Let's put up a full explanation.

Question Type: Match the Reasoning

Argument Core:

conclusion
Concert probably not properly promoted

why?

evidence
The concert didn't sell out.
and
Wells, a respected expert, said, "If doesn't sell out, not properly promoted."

MAKE IT MORE ABSTRACT
For our evidence, we need
- an expert who says "A --> B"
- a fact that says A happened

For our conclusion, we need
- B happened

(A) expert says "highly skilled -> probably survive"
a fact says "did not survive". Hmm, that's using the contrapositive.
Okay, do we conclude "NOT highly skilled"?
We do not.

(B) expert says something ... not conditional .... "probably"? Defer.

(C) expert says "properly repaired -> damage not noticeable"
fact says "damage IS noticeable". Okay, using contrapositive.
Do we conclude "NOT properly repaired"?
We do. Keep it.

(D) Not sure builder is expert, but expert says "No storm damage -> no repair for years"
Fact says "roof leaking". Is that storm damage? Feels loose. Defer.

(E) Expert says "properly conducted -> find lead in soil".
Fact says, "didn't find lead", so we should be concluding "not properly conducted".
Wait, what? This is concluding PROPERLY conducted? Eliminate.

(C) is the correct answer.

I'm a bit confused on why E is not correct. In your explanation you wrote, fact says "didn't find lead", when E actually says that it did. The answer choice reads, "Professor Y, who is an expert on the subject, said that the tests would find lead in the soil if they were properly conducted. So, since the tests DID find lead in the soil, they probably were conducted." I was between C and E but chose E because C mentioned a conclusive deduction rather than something that 'probably' happened. However, looking further, this appears to be an illegal reversal. If properly conducted then find lead in soil, while the conclusion reads find lead in soil so properly conducted. Any further clarification would be greatly appreciated!