We should recognize that this is a strengthening question, as the question stem asks: Which one of the following, if true, most strengthens the argument?
The stimulus begins with a definition of salmonella, which identifies it as a possible cause of intestinal illness. The second sentence tells us that this intestinal illness can be fatal, with an increased likelihood if not identified quickly and treated. So Salmonella can cause intestinal illness which can cause death, especially if you don’t know you have the illness; got it! Following this context about salmonella, we learn about conventional salmonella tests; basically, they suck. They are slow and can miss unusual variants, which since we know you want to quickly identify and treat intestinal illness, is pretty bad. Luckily, there is this new test which identifies whether salmonella is present based of a piece of genetic material which all subsets of salmonella possess. The argument concludes that it would be prudent for public health officials to swap the old conventional tests for the new genetic tests.
A key takeaway from this stimulus you should have is that we need more information about this new test. We know a decent amount about the old one, namely that it’s bad because it is slow and unreliable, but all we really get from the stimulus about the new test is that it is more reliable than the old one. A key detail we are missing is the speed of the test. A necessary assumption of the argument is that the new test isn’t too slow to be a good test for salmonella. As things stand, it is entirely consistent with what we know that the new test is 10 times slower than the old one! While there are always lots of ways to strengthen an argument, the fact that the stimulus mentions the importance of quickly identifying intestinal illness should have us on the lookout for an answer choice that fills the gap in our argument about the new test’s speed. Let’s see what we get:
Answer Choice (A) All this answer choice introduces is a disadvantage of the new test compared to the conventional test. Since our conclusion is that the new test should replace the conventional test, this answer choice actually weakens our argument.
Correct Answer Choice (B) Bingo! This answer gives us another important advantage of the new test over the old test, and fills in our assumption that the new tests aren’t too slow.
Answer Choice (C) Always anchor yourself in the conclusion on strengthening questions. We are looking for reasons why the new test should replace the old test. Our argument is about testing, not treatment.
Answer Choice (D) Ok? How often people get salmonella has nothing to do with relative superiority of the new tests to the old ones. Maybe if, for example, we were told it is hard to mass produce the new tests this answer might do something for us, but as the question is written this answer adds no support.
Answer Choice (E) Cool! We don’t care. Same as C, our argument and conclusion are all about the testing for Salmonella. This answer adds nothing to our argument.
We should recognize that this is a strengthening question, as the question stem says: Which one of the following, if true, would most help to support the conclusion about the German new-car market?
The stimulus begins by telling us about a recent upsurge in demand for used cars in Germany. It continues by further specifying that this demand is coming from former East Germans who can’t afford to buy new cars and who didn’t have access to cars before the unification of East and West Germany. For real-world context, after World War II Germany was split into the allied-controlled democratic West Germany and Soviet-controlled communist East Germany, which weren’t reunited until the fall of the Berlin Wall. Because there is now more demand for used cars than there are used cars available, the price of used cars has also risen. The next sentence tells us that West Germans, because of this rise in used car value due to East German demand, will be selling their old cars. From all of this information, the author concludes that the new car market will improve as well. This is the conclusion we have been tasked with strengthening.
The first thing we should notice once we finish reading the stimulus is that our conclusion is about new cars while all the support is information about used cars. There is a gap in the argument; specifically, what we need is a reason for why (i) increased East German used car demand, (ii) higher used car prices, and (iii) West Germans selling their used cars, could improve the market for new cars. Let’s take a look at the answer choices:
Answer Choice (A) While this answer choice does mention new cars, it doesn’t help us because it only does so in comparison to West German used car demand, which we know little about. Our conclusion is that the new car market will improve, it is a prediction about a future change. The relative size of one portion of the new car market to one portion of the used car market has no bearing on whether or not the German new car market as a whole will improve.
Answer Choice (B) This does nothing to support our prediction. For one, most European countries could not include Germany, in which case this answer would have zero impact on our prediction. And even if this answer explicitly says Germany was a part of this majority, this just gives a reason why buying a used car might be preferable to buying a new car, and no information suggesting there will be improvement in the new car market.
Answer Choice (C) Who cares? The average number of cars the majority of Germans own across their lifetime has little impact on whether the German new car market will overall improve after the changes in the used car market.
Correct Answer Choice (D) This is exactly what we are looking for. It bridges the gap between one of our premises, the one about an increasing number of West Germans selling their used cars, and our conclusion about the new car market. If West Germans generally buy a new car when they sell a used car, and an increasing number of them are going to be selling their used cars, it seems reasonable that the market for new cars will improve because their will be increased demand from these West Germans selling their old cars.
Answer Choice (E) We aren’t told if these North American cars are used or new, and this a preference of specifically East Germans who we know cannot afford new cars, so this information does nothing for our new car market prediction.
We know this is a strengthening question because of the question stem: Which one of the following, if true, most supports the argument above?
The first thing the stimulus does is give us a correlation; there is a certain strain of bacteria that is found in the stomachs of specifically ulcer patients. Further strengthening this correlation, a researcher with no ulcer history accidently ingested the bacteria and developed an ulcer. Talk about a workplace hazard! From these two correlations the author draws the conclusion that the bacteria strain causes the ulcers. A fair hypothesis to make, but we have to remember that correlation only implies causation, it does not guarantee it.
This stimulus has a very common structure for weakening/strengthening causal hypothesis questions. Correlation, more correlation, hypothesis of causation. Our job is to strengthen the hypothesis that it is the bacteria that are causing the ulcers. An answer choice may do that by eliminating an alternative hypothesis, providing an experiment whose results agree with the hypothesis, or one of many other ways. Let’s see what we end up with in the answer choices:
Answer Choice (A) Always stay anchored in the conclusion. The conclusion we want to support is about the causal relation between the bacteria and ulcers. This answer gives us a correlation between the bacteria and kidney disease. Interesting maybe, but definitely not relevant to our argument. A is incorrect.
Answer Choice (B) Good for the researcher, but not meaningful for us. Similar to A, this answer brings in other health issues to distract us. If we clearly understood the conclusion we are supposed to support, we should quickly see that this information isn’t helpful. B is incorrect.
Answer Choice (C) If this were a weakening question this answer choice might have promise, though the absence of evidence isn’t necessarily evidence of an absence. This is a strengthening question however, so this answer is terrible. C is incorrect.
Answer Choice (D) We’re all happy for the researcher (though if the recognized expert is ingesting dangerous bacteria, I don’t want to see what the non-experts are up to!), but his credentials don’t have any bearing on the author’s argument. D is incorrect.
Correct Answer Choice (E) E strengthens our argument by providing an experiment. It might have thrown you off that the experiment didn’t show people with bacteria having the ulcers, but we’ve already been told that correlation exists. What this answer does is give us an experiment strengthening the correlation by showing that where the ulcers aren’t present neither are the bacteria. From what we were told in the stimulus, maybe most people had this bacteria and only some developed ulcers. This study casts doubt on that possibility, and by strengthening the correlation, strengthens our causal hypothesis. E is correct.
Here we have a flaw question, which we know from the question stem: “The reasoning used by the gallery owner is flawed because it…” Right away we know our correct answer has to do two things: be descriptively accurate, and describe the flaw of the stimulus. We also know what the wrong answers will do - describe reasoning flaws we’ve seen before, but don’t like up with our stimulus. Once we have a clear understanding of the questrion’s objective, we can proceed into structural analysis of the stimulus.
The argument begins by telling us because this certain painting does not appear in Van Gogh’s catalog, we cannot guarantee its authenticity. But our speaker continues to say that because there are such incredible similarities between this painting and Van Gogh’s (brush strokes, color combinations, etc.) it must be the case this is almost certainly an uncatalogued work made by Van Gogh himself.
The conditional reasoning in the stimulus can help reveal the issue with the gallery owner’s argument. Our first sentence says because it's not in the catalog (/C) → there is no guarantee of authenticity (/G). Let’s write out the contrapositive. By negating both variables and switching their positions, we learn that if there is a guarantee of authenticity it must be the case that the art appears in the artist’s catalog because G → C. Our author continues past this premise to incorrectly conclude this particular painting must be a work of the author’s without being able to meet the necessary condition presented in our first sentence.
While the diagrammable relationships are useful, they are not required in order to predict what is wrong with this stimulus. Just because the paintings are similar in style to Van Gogh’s does not mean they came from his catalog. It could very well be the case that a talented amateur wanted to imitate the work of their favorite artist. Knowing that our correct answer choice will point out the weakness in the connection between similar styles to authenticity, we can proceed into answer choice elimination.
Answer Choice (A) This answer choice is descriptively accurate, but not the ultimate issue with our stimulus. Whether or not there is “general agreement” on a topic does not connect to our stimulus concerning a piece of art for which there is actually no apparent general agreement.
Answer Choice (B) Here is another answer choice that descriptively along with the answer choice but does not go far enough in reaching the actual problem in our stimulus. Accusing the argument of failing to cite “expert authority” does not weigh on our discussion about the likelihood a similarity leads us to some level of guarantee of authenticity.
Answer Choice (C) This is not accurate compared to the words of our argument. This answer choice says the only reason in existence for wanting a painting is to make a profit. But we do not have nearly the level of support required in order for us to say the argument makes a conclusion about the sole existing reason for wanting art in the first place.
Correct Answer Choice (D) This is exactly what we are looking for. This descriptively correct answer choice is the only one that correctly points out the more reasonable explanation - we’re looking at a painting that happens to be similar, but very well may not be painted by Van Gogh himself.
Answer Choice (E) Here we have another answer choice that is not descriptively accurate. Our argument does not attempt to push the conclusion on the basis of “self interest” of the reader. Without any connection to the self-interest or benefits included in making these catalog decisions we can eliminate this answer choice.
Here we have a flaw question, which we know from the question stem: “Which of the following describes an error of reasoning in the merchants’ argument?” Right away we know our correct answer has to do two things: be descriptively accurate, and describe the flaw of the stimulus. We also know what the wrong answers will do - describe reasoning flaws we’ve seen before, but don’t like up with our stimulus. Once we have a clear understanding of the questrion’s objective, we can proceed into structural analysis of the stimulus.
Our argument begins with a proposed law restricting outdoor advertising abilities in Penglai to small signs of a standard shape identifying a place of business. Next, we are introduced to the opposition. We learn some island merchants are protesting the proposed law because the overall amount of business being brought in would be reduced. The protestors’ base their reasoning on a government study where businesses with outdoor advertising tended to have a bigger market share than those who did not use outdoor advertising.
Ultimately, our speaker is concluding causation from correlation. Simply on the basis that business with outdoor advertising happened to have more business the speaker concludes the increased business is because of the use of outdoor advertising. Remember that our conclusion is something that has to be true on the basis of our premises. Just because these businesses have two qualities at the same time does not mean we can assume a causal relationship. It could be the case that a third outside factor impacts both business volume and outdoor advertising trends in the exact same way.
Knowing that our speaker incorrectly presumes causation from a correlation, we can proceed into answer choice elimination.
Answer Choice (A) This is not descriptively accurate. Our argument does not claim there are simply no reasons to enact the law. Instead, our argument claims that there is a bad impact that would follow from the enactment of the law.
Correct Answer Choice (B) This is exactly what we are looking for. This descriptively accurate answer choice is the only option that points out the existence of a third factor explaining the results in the government’s study. Answer choice B explains that businesses were more successful using outdoor advertising not because it raises the level of overall business available, but simply because it allows businesses to poach customers from their competitors. This points out the strength of the argument’s conclusion. Our speaker did not conclude that businesses with outdoor advertising were generating more business - instead, they were stealing business from their competitors.
Answer Choice (C) This answer is descriptively accurate, but not the ultimate issue in our stimulus. Whether or not the study is objective (100% factual without subjectivity) does not change the fact that our author incorrectly interpreted the meaning of the study.
Answer Choice (D) Here, we have another answer choice that is technically correct in description but does not identify the true issue with our argument. By telling us that the argument fails to establish that market share was exactly proportional to advertising, this answer choice does not attack the causal mistake seen in the argument.
Answer Choice (E) This brings us to our last descriptively correct answer choice that fails to describe the true issue of our stimulus. The consideration of this law being “constitutional” does not connect to any sort of the reasoning presented in the stimulus. Knowing our correct answer choice will highlight the flaw with the author’s interpretation of the study, we can eliminate this answer.
We know this is a strengthening question because of the question stem: Which one of the following, if true, most strongly supports the conclusion regarding a signaling function?
The first sentence gives us two facts about zebras and their stripes; all zebras have stripes, and the most widespread subspecies of zebra has the best defined stripes. A sub-conclusion is drawn from these facts that the stripes must have some kind of importance for zebras. Whenever you see a sentence that takes the form of “Since X, Y.” you should expect that you are being given a final premise followed by a conclusion. That’s exactly what we get, and from the final premise that the zebra stripes aren’t good for camouflage, the author concludes they must act a some kind of signal for other zebras. This is the signaling function conclusion we were told about in the question stem.
An important detail to note is that it is a signal for specifically other zebras. A good way to filter out wrong answers will be whether the explanation they offer involves three elements; (1) stripes, (2) signaling, and (3) an effect on other zebras. Let’s look at the answer choices:
Answer Choice (A) This answer gives us a correlation between defined stripes, and size and vigor. Always remember to anchor yourself in the conclusion on strengthening questions; we want to support a connection between stripes and a signaling function. This answer is irrelevant to that conclusion. A is incorrect
Answer Choice (B) If having stripes can make zebras harder to spot under certain conditions, that suggests that they do function as camouflage. This contradicts what we’ve been told in the stimulus, and by introducing an alternate hypothesis to our signaling function directly weakens what we want to support. B is incorrect.
Answer Choice (C) While this answer does pick up on the signaling function part of the conclusion, it has nothing to do with zebra’s and their stripes. We’ve been given no information that suggests zebra’s can temporarily change their color. C is incorrect.
Correct Answer Choice (D) Our conclusion is that the stripes must serve as some kind of signal for other zebras. This answer gives us an explanation of how the stripes could serve this function; Zebras react faster to shapes with stripes, so Zebras having stripes allows them to react to each other’s movement more quickly. This is the only answer with all three elements we mentioned. D is correct.
Answer Choice (E) Like C this answer might appeal in the moment because it mentions signaling, but it is important to stay anchored in our conclusion. We want support for the stripes acting as a signal, and therefore other potential signals Zebras might have are not helpful. E is incorrect.
Here we have a strengthening question, as the stem asks: Which one of the following, if true, would most support the naturalists’ prediction?
The stimulus begins with an opinion of some scientists; they believe mice must depend on human civilization for their continued existence. They support this conclusion with the claim that the relationship between mice and humans has diminished their ability to survive in nature. The author quickly makes their position clear and states that the scientists opinion ignores significant facts. While this is the author’s conclusion, it’s important to remember that our job is to specifically support the naturalists’ prediction.
To support his dismissal of the scientists opinion, the author cites several facts. First, Mice have managed to be the most widely distributed mammal after humans, despite threats from predators and humans. Second, they reproduce rapidly. Third, and more important to their survival than rapid reproduction, Mice can adapt to lots of different environments. To further bolster his case, the author quotes a prediction made by naturalists that mice would continue to survive even if the environment became too extreme to support humans.
This question is a good example of why it is important to read a question stem carefully. In this stimulus we are given three positions from three different groups: (1) the scientists’ argument that mice depend on humans, (2) the author’s argument that they don’t, and (3) the naturalists prediction that mice can survive extreme environments. The position we want to strengthen only takes up one sentence of this long stimulus! If we didn’t read the question stem carefully, we might misjudge answer choices based on how they affect the author or the scientists’ conclusion. Always read the question stem carefully.
The correct answer is the one which most strengthens the prediction that if the environment became too extreme for human life, then mice would be able to adapt and survive. Let’s take a look at the answer choices:
Answer Choice (A) We want to strengthen the prediction that mice will survive even if the environment is too extreme for human life. This, if anything, weakens that prediction by introducing a limiting factor on mouse survival. A is incorrect.
Answer Choice (B) The stimulus has already told us that mice reproduce rapidly, so this answer doesn’t add anything new as support. Even, worse it only tells us something about mice under optimum conditions. The prediction we want to strengthen concerns what would happen to mice in an extreme environment. It is safe to assume that an extreme environment is not optimum conditions. B is incorrect.
Answer Choice (C) This answer relies on conflating the ability of mice to adapt and survive if the environment becomes too extreme for humans with the ability to survive an environment without humans. This answer might seem appealing if you failed to read the question stem carefully and believe our job is to strengthen the author’s position. However, this information is irrelevant to the naturalist’s extreme environment prediction because nothing we are told indicates that pre-colonial America was an extreme environment. C is incorrect.
Correct Answer Choice (D) This answer gives us a case where mice did exactly what the naturalists predict they can do; they encountered an environment too extreme for human life, and were able to survive. Think of it as an experiment testing their hypothesis. An experiment whose results correspond to a general prediction will always, all else being equal, strengthen that prediction. D is correct.
Answer Choice (E) This information supports the scientists point about the dependence of mice on human civilization, but that isn’t what we’ve been asked to strengthen. For our naturalists prediction it adds no support. E is incorrect.
Here we have a flaw question, which we know from the question stem: “The reasoning in the argument is flawed because the argument…” Right away we know our correct answer has to do two things: be descriptively accurate, and describe the flaw of the stimulus. We also know what the wrong answers will do - describe reasoning flaws we’ve seen before, but don’t like up with our stimulus. Once we have a clear understanding of the questrion’s objective, we can proceed into structural analysis of the stimulus.
The stimulus begins with a fact; the new proposed cut to arts funding will make things difficult for arts organizations. Despite this, the author concludes the funding cut will not put these groups entirely out of existence. The stimulus ends with the main reasoning for the author’s conclusion, that we know these groups will continue to exist simply because they survived a budget cut in the past.
Our conclusion definitely does not follow from our premises here. Just because the group survived a budget cut in the past, that has no bearing on whether the groups will survive after this next cut. If anything, the groups seem even less likely to survive if they face one budget cut after surviving another budget cut in the previous year alone.
Knowing that our speaker incorrectly presumes because the arts survived one past cut they must survive this newly proposed budget reduction, we can proceed into answer choice elimination.
Answer Choice (A) This answer choice is not descriptively accurate. Without seeing somewhere in the stimulus where the speaker claims that the economy is without a doubt going to improve, we can eliminate this answer choice from consideration.
Answer Choice (B) Answer choice B is descriptively accurate, but not the ultimate issue with our argument. The justification of the existence of the arts group is not in question. Instead, our speaker focuses on whether or not they will be able to exist moving forward past this new proposed funding cut.
Answer Choice (C) This is not what we are looking for. Answer choice C goes beyond what our stimulus concludes by saying the speaker equated surviving with thriving. But nowhere does our speaker tell us the arts are thriving. For all we know, they exist at a 10th of the capacity as they did before the funding cuts. Our stimulus is concerned with the group existing at all - not whether that existence is a good one.
Answer Choice (D) The amount of our budget cuts is not the issue with our stimulus. Although this answer choice is descriptively accurate in that our speaker does not take this into account, our correct answer has to also hit on the exact reason why the speaker is flawed. The problem with our stimulus centers on a past/future assumption rather than the exact amount of those proposed cuts.
Correct Answer Choice (E) This is exactly what we are looking for. This descriptively correct answer choice points out the right issue in our stimulus by telling us that our speaker does not consider the already weakened position of the arts’ group. If the group survived one budget cut, they could very well be put entirely out of business by another round. The cumulative effect of those multiple budget cuts lines up well with our identification of the flaw in the stimulus.
We can identify this question as Method of Reasoning because of the question stem: “In countering the original conclusion the reasoning above uses which one of the following techniques?”
When dealing with a Method of Reasoning question, we know we are looking for an answer choice that correctly describes the structure of our entire argument. Our correct answer is going to fit the argument exactly. Our wrong answer choices likely explain argument structures we are familiar with, but that simply don’t apply to the specific question we are looking at. Knowing what the right and wrong answers are going to do, we can jump into the stimulus.
The argument begins by telling us about a correlation; those who play bridge tend to have better short-term memories than those who do not play bridge. We know right away that the presence of two qualities at the same time does not mean they caused each other. The argument proceeds by affirming this exactly. We are told that although this correlation was previously concluded to indicate a causal relationship meaning bridge causes better short-term memory, it is just as likely that having a better short-term memory makes the game of bridge more intriguing to that particular group of people.
Ultimately, our stimulus outlines an incorrect conclusion on the basis of a correlation and then goes on to explain another possible interpretation from the evidence. Knowing this, we can jump into answer choice elimination.
Answer Choice (A) If our stimulus were challenging the representativeness of the study included, we would expect the argument to bring up the number of people involved in these different groups or how well these groups represent the rest of the population. Without this information we can eliminate answer choice A.
Answer Choice (B) This answer accuses our stimulus of drawing a conclusion about what is considered “appropriate therapy.” Without this emphasis in the text we can eliminate B.
Answer Choice (C) Our stimulus does not depend on some sort of misunderstanding of the facts involved in the scenario. Thus, we can nix answer choice C.
Correct Answer Choice (D) This is exactly what we are looking for! This is the only answer choice that identifies the alternative possible explanations for the facts presented in the argument.
Answer Choice (E) This answer choice is tricky. But our stimulus does not go quite far enough to say it is describing a flaw of the previous conclusion. Because our stimulus only points out the existence of another possible conclusion we cannot confirm answer choice E.
We can identify this question as Method of Reasoning because of the question stem: “Jonathan uses which one of the following techniques in his response to Lydia?”
When dealing with a Method of Reasoning question, we know we are looking for an answer choice that correctly describes the structure of our entire argument. Our correct answer is going to fit the argument exactly. Our wrong answer choices likely explain argument structures we are familiar with, but that simply don’t apply to the specific question we are looking at. Knowing what the right and wrong answers are going to do, we can jump into the stimulus.
Immediately we should make note of the two speakers at play. This means we could possibly be dealing with two different conclusions with different levels of support. Our first speaker, Lydia, tells us seabirds often become entangled in equipment owned by fishing companies. Lydia concludes on the basis of this that the fishing companies should assume responsibility for the medical treatment of these animals.
Lydia’s position makes an assumption here. If our conclusion tells us that something should happen, our evidence needs to give us reasoning to guarantee the outcome should occur. Perhaps, for instance, there is a law indicating those causing harm to animals should be responsible for them. But without this information the evidence does not automatically lead to the conclusion that the fisherman should be responsible for anything.
Jonathan does not quite hit the assumption out of the ballpark. In response, our second speaker concludes the proposal should not be adopted because the most injured birds won’t be able to return to the wild. Remind yourself here of how uncertain the number of “most injured birds” is. Perhaps 99.99% of the birds are injured mildly and 0.01% are the “most injured” with extensive injuries. Putting things into context, Jonathon’s response asking us to consider a group that could be impossibly small and irrelevant to Lydia’s ultimate conclusion.
Knowing that we are looking for an answer choice that will highlight Jonathon’s use of a small subset of these animals in a (poor) attempt to weaken Lydia’s reasoning we can jump into answer choice elimination.
Answer Choice (A) This answer choice accuses Lydia of a personal attack. But without any reference to Lydia’s motivation or other personal characteristics, we have to eliminate this answer from contention.
Answer Choice (B) We can eliminate this answer for a similar reason why we eliminated answer choice A. Like a personal attack, B accuses Lydia of being wrapped up in their personal interests - an attack we do not see used as the reasoning for Jonathon’s conclusion.
Answer Choice (C) This answer choice goes too far in the extreme. By accusing our second speaker of not wanting to interfere with wildlife in any way, this answer choice claims Jonathon’s conclusion goes even further than we can see in the stimulus.
Correct Answer Choice (D) This is exactly the answer we are looking for! This is the only answer choice that references Jonathon’s use of the sickest group of birds in an attempt to weaken Lydia’s argument.
Answer Choice (E) While Lydia’s feelings are addressed at the beginning of Jonathan’s argument, this is not the reasoning used to prove Jonathon’s main point. They claim we should not adopt the proposal because of this sub-group of birds. Not because of Lydia’s personal feelings in the matter.