#12 - West: Of our company’s three quality control

[Administrator]

Please post below with any questions!

[lll7]

Why is B wrong and E right?

Thanks

[Emily Haney-Caron]

Hi lll7,

The argument presupposes that, if half of the appliances returned were inspected by Haynes, Haynes must be the worst. But that's incorrect, because Haynes inspects significantly more than half, so if only half returned are from Haynes, that means Haynes isn't clearly worst.

Young isn't questioning the relevance of the conclusion, though; that would mean saying the conclusion (that Haynes is the worst) doesn't matter. Instead, Young is saying the conclusion can't be drawn at all.

Make sense?

[Iri]

Hi, why is the answer not C? A premise and presupposition seem to be the same thing to me, and how is denying the accuracy any different from disputing the accuracy? Thank you!

[Kristina Moen]

Hi Iri,

You are correct that a presupposition is a premise. A presupposition is like an assumption. It is an unstated premise in support of the conclusion.

Here, Young is not disputing the accuracy of one of West's stated premises. The only premise that West states in support of his conclusion (Haynes is the worst) is that half of the appliances returned were inspected by Haynes.

If Answer choice (C) were correct, we would see something like this:
Young: But of the appliances returned, Haynes did not inspect half. You're mistaken.

But Young does not dispute this. Young states an additional premise - that Haynes inspected significantly MORE than half of the appliances. This additional premise weaken's West's conclusion. Here's why:

West's conclusion is based on the unstated premise (aka presupposition or assumption) that Haynes must have inspected less than half of the appliances. He's basing his conclusion (Haynes is the worst) on the idea that the appliances he inspected were more likely to be returned than the appliances that other people inspect. If Haynes inspected 90% of the appliances, and yet only half of those returned were inspected by Haynes, then that would mean that the appliances he inspected were actually less likely to be returned.

[mN2mmvf]

Hi!

I opted against (E) because I didn't understand why it was necessarily true that West was presupposed that Haynes must have inspected less than 50% of the appliances. I get that, in general, 1) if Haynes had in fact inspected more than 50%, he'd actually be a better-than-average inspector, 2) if he inspected 50%, that'd be exactly what we'd expect of any inspector, and 3) if he inspected less than 50%, he'd seem to be a bad inspector with a disproportionately high defect rate. And I see that Young is saying, "Haynes is actually pretty good!" because Young is using accurate information, making these proportional comparisons correctly. But I don't see why that entails Young is denying a presupposition.

My problem with (E) was that, Why should we assume West's argument is actually about proportionate expectations at all? Yes, if West were comparing Haynes's defection rate to the percentage of the appliances Haynes inspected, West would necessarily be presupposing that less than half of the appliances were inspected by Haynes, in order for his argument to hold. (And then Young simply denies the factual accuracy of that presupposition, destroying the argument.)

But maybe West is just using an entirely different "logic," which is also wrong but for different reasons? Maybe West is just saying, "there are three inspectors, and Haynes is only one of them, so the fact that 50% of the appliances returned were inspected by Haynes makes him a bad inspector, because 50% is higher than the 33% I would have expected." Why are we to charitably assume that West is saying anything sensible at all?

I thought that no matter how Young may interpret West's argument though, in all cases Young clearly is responding that West shouldn't possibly conclude anything as extreme as saying that Haynes is the worst. Maybe Haynes is bad for many reasons, defection rate possibly just one among them, but we know at very least that there's one reason to be less extreme in our condemnation of Haynes. That's why I thought (D) was a better choice than (E).

[James Finch]

Hi MN,

(D) is incorrect for a couple reasons:

First, Young doesn't make an actual argument, but merely points out a flaw in an unstated premise, and comes to no conclusion other than the implied one, that Haynes is not the worst inspector. But Young does not argue for that implied conclusion, and West's conclusion could still be true for reasons other than the ones that Young rejects.

Secondly, the conclusion that West makes is difficult to imagine as less extreme; West says that Haynes is the worst of the top three quality control inspectors, but there are only three. So if not the worst, what would Haynes be? Average? Surely not the best? Maybe simply not the best?

(E) works as an answer because in order for West's conclusion to be true according to West's own premises, Haynes would have to have inspected considerably fewer than half of the appliances sold; if, as (E) states, Haynes inspected considerably more than half sold, but of those, only half of the total returns came from the more than half sold that Haynes inspected. So Haynes's ratio of returns-to-sold products must be better than at least one of the other 2 top inspectors, meaning he could not possibly be the worst according to the criteria West uses.

I hope this clears things up!

[freddythepup]

Hi James,

A small question on this one. I get why E is the correct answer. But you mentioned that in B, when it says "questioning the relevance of the conclusion" means that it's saying the conclusion doesn't matter, not that it isn't true. My question is, isn't this what Young is saying in a way? By bringing up another assumption that Haynes actually inspects way more than half of the appliances in a year, he's telling West that his conclusion doesn't matter/can't be drawn? At least this is how I read it. The reason being that if Haynes inspects so much more appliances than West believed, then how could West make the conclusion he did that Haynes is the worst, he can't. Can you elaborate on why my thinking here does not work? Thanks!

[Claire Horan]

Hi Freddy,

The problem with your previous thought process is actually right there in your question.

By bringing up another assumption that Haynes actually inspects way more than half of the appliances in a year, he's telling West that his conclusion doesn't matter/can't be drawn?

Saying something doesn't matter isn't the same as saying it isn't valid. The conclusion is that "Haynes is clearly the worst" of the three quality control inspectors. If Young were questioning the relevance of West's conclusion, he might say something like, "Who cares if he's the worst at quality control inspecting? He has many other roles at our company that he is good at." That kind of response is very different from telling West that his conclusion is invalid.

I hope this helps!

[oli_oops]

Hi powerscore staff,

thanks for all your explanations, though I still don't quite get why E is correct.
I thought Young's argument is merely to put things into perspective without denying what West said - "out of the returned appliances, half of them were inspected by Haynes". Young was basically just saying "yeah, out of the returned appliances half of them were indeed inspected by Haynes, BUT, to put things into perspective, Haynes actually inspects a total of more than half of all appliances, returned or non-returned".

Does my reasoning make sense at all...? Can someone explain to me whether/how my reasoning is correct/incorrect?

Thank you for all that you do!
oli