Q20 - A recent study confirmed that

[ohthatpatrick]

Question Type:
Explain Discrepancy

Stimulus Breakdown:
Fact 1: In general, more salt leads to higher BP. And people with high BP who cut their salt intake have lower BP.
Fact 2: Some people eats tons of salt and manage to maintain low BP.

Answer Anticipation:
Given that [more salt usually means higher blood pressure], how is it that [some people eat tons of salt but maintain low blood pressure]? Not much of a paradox here, in the sense that the first fact is that "salt intake TENDS TO increase blood pressure". "Some", in the last sentence, means "at least one". So telling us that "salt intake TENDS to increase blood pressure" is compatible with telling us that "for some people, that's not the case". Even though there isn't really a paradox, this IS a paradox question, so we should probably expect to hear about some OTHER factor that's true of the weird high salt / low BP people, some factor that explains how they get low BP in spite of high salt.

Correct Answer:
E

Answer Choice Analysis:
(A) We're trying to explain the weirdos in the last sentence. This has nothing do with them.

(B) Tempting Could this explain the weirdos in the last sentence? Even though they DO eat lots of high salt, something ELSE in their diet is keeping their blood pressure low? Ultimately, this answer fails because it's talking about dietary factors associated with HIGH blood pressure. Those factors, if absent, would presumably be associated with NORMAL blood pressure. Meanwhile, the weirdos in the last sentence actually have VERY LOW blood pressure. The dietary factors (B) is describing are other ways to have high blood pressure, not a way to get to very low blood pressure.

(C) Talking about which type of dietary change best gets someone to lower blood pressure has nothing to do with our goal of explaining the weirdos in the last sentence.

(D) Cool fact, (D). Unfortunately, we're looking for more info about the weirdos in the last sentence, who had very HIGH salt intake.

(E) Yes! This contributes to our understanding of the weirdos in the last sentence. Essentially, it allows us to STILL believe that salt intake increases blood pressure. It's saying that for these weirdos, their initial blood pressure reference point is VERY, very low, and they end up eating a lot of salt in order to raise their blood pressure up to the level of "very low".

Takeaway/Pattern: Notice that the idea in the first sentence is RELATIVE (higher/lower blood pressure), while the ideas in the last sentence are ABSOLUTE (high / low). If we said, "Supposedly, studying more tends to raise your score. So why is Debbie, who studies more than anyone, only getting a 60% on the test?" It could just be that Debbie's initial reference point was much lower. If she started at a 20%, and her studying got her to a 60%, then we would say that studying is having its expected effect.

#officialexplanation

[bnuvincent]

I found B temping, could you please explain?

[ManhattanPrepLSAT2]

(B) is definitely a very tempting answer.

For me, the key to success on a question such as this one is to have a very very specific sense of what the discrepancy is. In this case, they've written the argument in such a way that it is easy to misread, but here's the discrepancy clearly laid out:

People with high blood pressure who cut salt intake lowered blood pressure.

but

Some people with low blood pressure maintain low pressure even though they consume a lot of salt.

In a general sense, knowing that factors other than salt intake can impact blood pressure can help explain the differing results in different individuals, but notice that (B) doesn't help explain the specific discrepancy in this argument.

(B) is not just saying that other factors influence blood pressure, but rather that other factors influence high blood pressure. This doesn't explain why some people with low blood pressure maintain it while taking in a lot of salt, while those with high blood pressure can reduce it by taking in less salt.

This is a really subtle issue. Here's an analogy that might help:

Ted, who is overweight, went on a diet and lost weight. Bob, who is skinny, eats a ton but never gains weight.

An answer such as "Factors other than diet impact weight" would be correct, because it explains why Ted and Bob have different outcomes - specifically why Bob doesn't gain weight even though he eats a ton.

However, an answer such as "There are several reasons why people become overweight" doesn't address the discrepancy directly (doesn't explain exactly why dieting helps Ted, nor, more importantly, why Bob is skinny).

[tiourina]

Thank you - Mike.
The analogy was very helpful.

[robowarren]

That explanation was super helpful! Thank you. While I picked up on the discrepancy, I had still picked B because I thought it was the "best" answer, because none of the other ones seemed right.

Can you explain why E works? I still don't see how their salt cravings would impact anything here.....

Thank you!

[timmydoeslsat]

Answer choice E's use of salt cravings is a way to show us that these people with abnormally low blood pressure are having a high intake of salt for their blood pressure not to drop even lower than abnormal.

[jamiejames]

So we're meant to equate "very" with "abnormal"?

[timmydoeslsat]

Yes. To say that someone has abnormally low blood pressure is to say that something has very low blood pressure.

[Joetrot88]

*First note that this is not an argument, it's a set of facts.
To correctly solve this (or any) discrepancy question we are posed with 2 situations and an answer choice must meet the following 2 conditions
1.) it must prove one or boththe situations to be correct. (can just prove one to be correct and allow the other to be correct)
2.) it cannot prove either of them to be wrong

Okay after reading the stimulus, the 2 situations in the study we learn of are ...

1.) people with high blood pressure who vastly decreased their salt consumption had lower blood pressure
2.) some people who had very high salt intake both before and during this study maintained a low blood pressure

These 2 situations are based on the important fact that the studyCONFIRMED salt intake tends to increase blood pressure

One thing you may ask yourself during the course of this argument is... hmm why weren't people with low or adequate blood pressure mentioned?? Notice that the second situation mentions people with high salt intake... not high blood pressure.

Also during your pre phrase, you may ask yourself that maybe something else may be the cause of the blood pressure fluctuations... I like your thinking, but be careful here... the stimulus tell us that salt intake in fact DOES INCREASE blood pressure, thus we cannot take this fact away from the argument and from this we are able to assume that DECREASING salt consumption should LOWER blood pressure(as stated in situation #1). This is why (B) is incorrect. It doesn't matter if anything else is a dietary factor other than salt intake, because this study and information in the stimulus is solely focused on salt intake and the effect it has on blood pressure which bases its findings on a confirmed fact established by the stimulus.

(E) is the CORRECT answer here. It states that Persons suffering from abnormally low blood pressure have heightened salt cravings, which ensure that their blood pressure does not drop too low.

This is correct because 1.) it proves/allows both situations to be correct 2.) it does not prove either to be false

It shows that people with ABNORMALLY low blood pressure crave salt intensely as a safety mechanism to make them consume salt in order to bump their EXTREMELY low blood pressure to a higher level.. maybe to a regular low, or maybe even an adequate or high blood pressure.. either way who cares? we're only concerned that salt in fact does in fact cause blood pressure to go up. This proves situation #2 to be correct directly. It also allows situation #1 to be correct by simply not disproving it. This answer choice is a great explanation for our contradiction and does not harm the outcome of either of the events.

[rgrijalb]

B is wrong simply because of the word "associated". To take these other dietary factors as causation would be erroneous logic, hence cannot possibly be a explanation to a resolve the paradox .

[Alvanith]

I am convinced by Mike's explanation, but I not convinced by the explanation from one above post.

One post says because the stimulus gives a CONFIRMED study, we cannot take this fact away. Sure, right, but you forget something else may balance out the increase of blood pressure brought by salt intake. This is to say, we must accept salt intake tends to increase blood pressure, but we cannot deny there might be other things that can decrease blood pressure.

B could be a contending answer if not including the problematic word "high" since, for those high salt intake low blood pressure guys, there might be something else that actually help them to balance out the increase of blood pressure brought by high salt intake. The answer just says "associated" rather than explicitly saying "increasing" or "decreasing." Imagine this, if the high salt intake can increase blood pressure by 50 units but a really healthy diet these guys are taking can decrease blood pressure by 80 units, then balance is -30 units and that could fall within the lower end of blood pressure chart. In this way, we don't challenge the confirmed study but we potentially solve the discrepancy.

Another post says the word "associated" is problematic because of faulty reasoning? Is he or she saying the explanatory power from this answer is simply too vague to be a plausible explanation? I would like to hear more about this. Thanks in advance.

[rsmithpt267]

Isn't the point of an Explain the Discrepancy question to fill in the gap with one of the answers which allows both to be true and explains both premises? I don't see how E contributes to the 1st explanation of people with HBP reducing it by decreasing their salt intake. How can heightened salt cravings for abnormally low BP people explain why people with HBP that reduce salt intake reduce their BP. E only talks about people with LBP. Isn't this the same problem that B has? B only talks about people with HBP and leaves out those with LBP?

Simple Analogy:

1. People with High Cholesterol who reduced their fatty food intake, reduced their Cholesterol.

2. Some people who eat a very high amount of fatty foods have low Cholesterol.


How would an answer (similar to E) such as "People with abnormally low Cholesterol have cravings for fatty foods, which ensure their Cholesterol does not drop even lower" tell us anything about people with HC reducing it by reducing fatty foods.

To me, an answer which says (similar to B)- Fatty foods is only one factor that is associated with High Cholesterol, helps explain why some people have low Cholesterol even though they eat fatty foods (family history, other health issues etc) and why people with High Cholesterol can reduce it by reducing fatty food.

Any help is appreciated.

[olaizola.mariana]

rsmithpt267, I think your answer that's similar to E would indeed help to explain the discrepancy by allowing fatty foods to affect your cholesterol levels. For the person with high cholesterol to begin with, reducing fatty foods leads to lower cholesterol. For the person with very low cholesterol to begin with, continuing to eat large amounts of fatty foods would constantly boost their cholesterol enough so that their cholesterol level doesn't drop even lower (than the already very low level). The discrepancy is solved because the amount of fatty foods eaten can still be said to have an effect on cholesterol (in the first instance by lowering it, and in the second instance by raising it). Hope that helps.

[mswang7]

Group 1 - High BP people cutting salt intake resulted in lower BP.
Group 2 - people with high salt intake that have low BP.

Prephrase Group 2 offset their salt intake with other counterbalancing foods

A. Only discusses group 1. We need to link/relate the 2 to resolve out discrepancy
B. Sounds promising but I think this would apply to both groups
C. Only discusses group 1
D. Neither of the groups we're trying to explain have low salt intake. Even if you say this applies to group 1, this doesn't explain group 2
E. This is saying for members of group 2 might be different because their "starting point" is a lot lower than the average person. This makes sense because salt intake is still driving their BP higher, just not as high as normal people/ group 1 because of the lower starting point.