I feel like the correct answer here strengthens but is overly strong for a NA.

For NA when we negate, aren't we supposed to be on the hunt for whether an interpretation of a negation can still be squared with the argument (so in a sense, we should be looking for the interpretation most friendly to the original argument)? And if we find it, that means that answer choice is not a NA?

In this case, the negation of D is "some of the least enthusiastic are among the most committed." But it need not be the case that any of those students who sit at the overlap are the ones who passed. We can have an overlap of least enthusiastic and most committed and, at the same time, have exactly 0 of the overlap students pass and have only least enthusiastic students who aren't most committed pass. In which case, the "proving ground" mechanism failed and the argument stands, because the mechanism fails if a single student who is not most enthusiastic passes.

Instead for this to truly be a NA, I think we needed the correct answer to say "Some of the least enthusiastic students who passed are not among the most committed." I believe this would negate to "All of the least enthusiastic students who passed are among the most committed." There is no interpretation of that negation that lets the argument stand. The "filter" the class aimed for completely worked.

I don't exactly agree with his support for answer choice D for #17. In my view, what he points to are undesirable consequences, not unreasonable consequences. I found the support for this answer, instead, in the first paragraph of Passage A where the author cites Saint Augustine and says"to proceed against lies by lying [the view] would be like countering robbery with robbery [the unreasonable consequence of following this kind of tit-for-tat view]." That outcome would be in-keeping with a definition of unreasonable as closer to"nonsensical."

I'm confused how we are interpreting "on average" here. Are we taking it to more loosely mean that it's what is usually the case for any specific country? So they tell us "on average" the value is 70%, and then if we refer to any random country, we just assume it's probably 70% for that specific country?

Contrast this with the strict definition of the term, which would mean we took a pile of countries and averaged their % tourism revenue going to foreigners and arrived at 70%. This wouldn't let us know the % for any individual country, but we would know that it would be impossible to arrive at this average without at least one more individual countries having a % tourism revenue going to foreigners of equal to or greater than 70%.

Considered in isolation/not with reference to the test question here, is the argument in AC B valid? The form is: A → B, likely /B, so likely /A.

#help

Also feeling uncertain about this. By saying we have to know what would happen in the cases where the gov't doesn't fall, he seems to be implying here that a correlation has to be bidirectional. (But I don't think he's confirmed as such in the lesson work on this).

Does anyone else have a view on whether this distinction seems to be the case? If true, it would mean that something like observing that students get higher test scores with increased hours of study would just be an association/a coincidence/a concurrence, and not a full-on correlation unless the converse also held, that it was also true that students got lower test scores with decreased hours of study.

If this doesn't sit right, what is everyone else's understanding of what distinguishes a coincidence from a correlation proper?

I scored 8 points lower than my average PT score and 2 points lower than my diagnostic a year ago. I've been studying full time, so these results were baffling and demoralizing. For what it's worth, I had the double RC section. Going off of Reddit, it seems like the folks with that iteration of the test saw the biggest deviations from their average PT score, for some reason. (Of course, my LR training tells me this could just be a coincidence.)

I'm kinda in the same boat re current scores and score target for October, so maybe take my advice with a grain of salt. But in studying LR and looking for patterns, I've found that a different way to slice the content, rather than by question type, is by argument type which the curriculum sorta does (for example separating out questions based on formal logic and those based on empirical premises) but isn't as thorough as I'd like. So maybe if you sort and study your past questions wrong along that major axis - formal logic vs everything else - and then subcategorize from there, you might find patterns you're not otherwise seeing.

I think the fact that the stimulus says that the zoos themselves maintain the breeding stock tells me that, even if the actual breeding doesn't happen in the part of the zoo the public interfaces with/associates with attending a zoo, it happens on a property that the zoo owns and manages and is considered part of the zoo operations....thus is every much part of/in the zoo as the part customers go to.

It doesn't read to me like AC E is attacking the link between the premise (correlation) and conclusion (causation). It reads to me like it is directly contradicting the conclusion of the argument.

I wonder if it's only permitted here because they didn't directly say "the nucleus is known not to be causally connected to disease X" but instead said the region the nucleus is located in and the disease that X is a subtype of. Maybe that wording creates the necessary space for this to not just directly reject the conclusion.

The conclusion says that a switch BACK is unlikely. I think that one word is the key to disregarding the answer choices talking about natural gas equipment costs. It doesn't matter how those costs fluctuate, the swath of people the conclusion concerns itself with is those who have already switched and, as a result, already purchased and own natural gas equipment.

I think there is something subtle going on here with the wording "it is not surprising" in the conclusion. On a third pass through on BR, it led me to look for a principle with a predictive component, which only D offers (with "a business WILL improve"). If the principle says x will be the outcome, then that outcome should not be surprising.

Has anyone noticed any other questions with this type of wording in the conclusion? #help

Has anyone else found any other questions that appear to hinge entirely on the distinction between an"argument" and a "claim" that J.Y. noted in this video? #help

What is the negation for "should/ought to do something"? As in, say we wanted to contrapose the main argument that ends with the conclusion "should return the book at the promised time". It sits wrong with me that it would be "should not return the book at the promised time" (which might then be synonymous with "wrong" in AC A). Maybe it's something like "don't have to"/"not obligated to"? So you're free to return or not return the book at the promised time...

#help

For #2B I actually think this answer choice is wrong not because of the "how to measure" part, but because it speaks of measuring "lichen growth rates" instead of just lichen growth. They tell us how they measure lichen growth, that is, by measuring the diameter of the largest lichen on a boulder. It seems they then take this measurement of lichen growth and compare it against growth rates known for a given species (citing one species typical growth rate as 9.5 mm/century) to determine how long the lichen has been growing, to date that growth, telling us when lichen first established themselves on that boulder.

For # 2E "an application of...their use in studying past earthquakes" is precisely to predict future earthquakes. The application of, the usefulness of studying past earthquakes is to predict future earthquakes, as the last sentence of the first paragraph tells us.

I think it might be more helpful for us to turn the "likely" in the question into a most statement (as JY as done for other questions). And then it becomes really obvious that upon failing the necessary we can't simply contrapose back.

I'm with you on this one. It's very clear that in AC A the expression"M always cures athlete's foot" is M → cure, which takes M to be sufficient to cure athlete's foot. But it's not as obvious to me that the expression "evidence showing only that M can cure athlete's foot" is the same as saying "only M can cure athlete's foot" (cure → M) rather than "M can cure athlete's foot."

But perhaps rather than getting hung up on the specific placement of the "only" we're supposed to use our understanding of what the word "only" means in context, and in, context of the study in which just M and N were used to treat athlete's foot, the evidence from the study showed that only M can do so. And that's what this part of the answer choice is trying to say.

Sidebar: If there was no use of the word "only" and the idea of "only" was not present whatsoever, and instead the expression had been "M can cure athlete's foot", would there be a proper lawgic translation for this? Is there a relationship between "can" and "cannot", where can is the negation of cannot? #help

Applying the likely = most translation from question #24 of this same section, wouldn't AC B translate to the following?:

A → (most) B → (most) C , therefore A → (most) C

And, if so, had the reasoning in the stimulus been A → B → C therefore A → C, wouldn't this answer choice still have been an incorrect match because we can't say an "if A, then B" argument is the same as an "if A, then likely B" argument? #help

I think this analysis in on point. I originally picked D because I incorrectly interpreted the "any" in "any substances of medicinal value" as something more like "at least some" and then negated it to "none." If that was the wording, this answer choice would indeed be required.

But instead, the "any" (which is a group 1 indicator) more appropriately translates to "all" (also a group 1 indicator). So then the answer choice states that all substances of medicinal value will be found. "All" negates to "not all," so the negation of this statement is "not all substances of medicinal value will be found." Or, put another way, some of the substances of medicinal value will not be found. This argument doesn't fall apart if we don't find all the remaining substances of medicinal value. If we find at least one novel substance of medicinal value that doesn't exist anywhere else and that we would lose if the rainforests aren't preserve, the argument stands.

The combination of conditional and, I suppose, correlation threw me off. Would be great to get a confirmation that this is what is afoot and is why JY didn't write the conditional arrow with the "as increases, _ decreases" #help.

Also assuming that is what we have here, it still leaves me confused about how and when to properly combine them. I was honestly quite surprised when JY substituted "unlikely" (in the conditional) for decreased likelihood (from the correlation)

So, to be clear, the conclusion of this argument is the entirety of the conditional statement "if steel manufacturing plants could feed the heat they produce into thermophtovoltaic generators, they would greatly reduce their electric bills, thereby saving money"?

I find that conditional, or "qualified," conclusions like this trip me up. I'd like to study more questions with these types of conclusions. Does anyone know of some other questions that fit the bill? #help

For AC E, my understanding of math is likewise that inversely proportional would require a constant rate...that is, for every increase in phosphorous level, there is a same decrease in oxygen level. Has anyone noticed if this strict interpretation of inverse/direct proportionality has been decisive in other questions/answer choices? #help

When I did this question, though, my thinking of why the inverse proportion relationship wouldn't hold is that an inverse proportion requires 2 pieces to a relationship: when value A increases, value B decreases AND when value A decreases, value B increases. From the information provided in the stimulus we can only confirm one half of the required relationship (when A, phosphorous levels, increases, B, oxygen levels, decrease) and do not know if the other half of the relationship obtains. That is, we don't know if a decrease in phosphorous levels will cause an increase in oxygen levels.

I had a similar interpretation of the layout of the argument (If [A → B] then [A → C], but a different approach to addressing the new premise (all babies do not know dictionary definitions, /B).

Only saying /B does not give us enough information to draw a conclusion from the relationship "if [A → B] then [A → C]". We don't know if we've satisfied or failed the sufficient [A → B] (and surely can't tell what happens to the necessary [A → C] since there is no B in that portion).

We would either need to be additionally told /A to satisfy the sufficient and trigger the necessary [A → C], or we would need to be told A to fail the sufficient (which would be negating the A → B relationship), and the rest of the rule would fall away.

Answer choice E describes this situation, the negation of the A → B relationship. It says if, in addition to the /B we know, we find A holds, then the relationship A → B is negated, i.e. it is not always the case that A → B.