#12 - Vitamin XYZ has long been a favorite among health food

[Administrator]

Complete Question Explanation

Must be True. The correct answer choice is (B)

As we know, when a question asks what inference follows from the stimulus, it is a must be true question and we must be able to point to something specifically going on in the stimulus to support our answer choice. When an inference is involved in a must be true question, it usually means that we are going to take the stimulus information to its next logical step. Here we are told that in a recent study, those who took vitamin XYZ every day for two years had a lower risk of heart disease than those who did not. The legitimacy of the study is furthered by the information in the last sentence, stating that researchers did correct for differences in relevant health habits. From the information given in the stimulus, there is no reason to believe that the results for the study group would no translate to the population as a whole.

Answer Choice (A): Since this is a must be true question, and the stimulus gives us no information on side effects, we should be immediately leery about this answer choice. While we know from the stimulus that vitamin XYZ can reduce the risk of heart disease, we have no idea what the side effects of this or any other vitamin might be, and therefore cannot infer that taking the vitamin is worth risking the side effects.

Answer Choice (B): This is the correct answer choice. Since the study showed a 40 percent lower risk of heart disease, and there is no reason for us to doubt the results of the study, we can follow with an inference that there will be a comparably lower risk of heart disease for those taking the vitamin on into the future.

Answer Choice (C): While the 40 percent lower risk of heart disease was the average for the study group as a whole, there is no information in the stimulus that would support an inference that this 40 percent decrease will be the exact number enjoyed by everybody who takes large amounts of the vitamin.

Answer Choice (D): As we mentioned in regards to answer choice A, there is no information in the stimulus regarding side effects or other negatives to taking vitamin XYZ. All we know is the one positive effect mentioned in the stimulus.

Answer Choice (E): This answer is too broad because it refers to vitamins as a whole and refers to the generic result of "good health". All we know from the stimulus is that taking this one specific vitamin seems to have this one specific positive result. Any broader inference is not supported by the information provided.

[lsat2016]

Is another reason why C is wrong because the study compares vitamin xyz users v nonusers and not a measurement of improvement among xyz users (this would look something like on average, xyz users improved 40% compared to 2 years ago)? I eliminated C for this reason and wanted to make sure that this is a valid reason.

Thank you

[Clay Cooper]

Hi Lsat2016,

Yes, I think you are correct in eliminating answer choice C for that reason.

For instance, what if Li had already been taking xyz daily for ten years prior to the beginning of the two-year period the answer choice talks about? In that case, we would have no reason to expect her risk of heart disease to have decreased over the two years.

Good job! The hard work is paying off!

[MikeJones]

Complete Question Explanation

Answer Choice (E): This answer is too broad because it refers to vitamins as a whole and refers to the generic result of "good health". All we know from the stimulus is that taking this one specific vitamin seems to have this one specific positive result. Any broader inference is not supported by the information provided.

Very good explanation. Seeing as this is the only other appealing answer choice, I think it's important to point out that not only is "good health" too broad and generic (which is why I discounted E); I also noticed that it says "multiple vitamins," whereas the stimulus only refers to food enthusiasts' opinion on Vitamin XYZ. We just don't have any info on "multiple vitamins."

[nicholaspavic]

Hi Mike,
Exactly! That is overly broad. Thanks and keep up the good work!

[martinbeslu]

I originally kept C as a contender and I chose B but I wasn’t sure why exactly other than that something just felt wrong about C. I mean, if the average person that takes vitamin XYZ has a 40% lower chance of getting heart disease then I would think that her likelyhood of getting heart disease would go down the same amount, all else being equal. However, all else is not necessarily equal for Li. After reviewing answer C further it makes sense that Li’s health situation specifically could have changed drastically during the past two years. Maybe she started eating fried chicken every day and that increased her chances of getting heart disease by 40%, therefore cancelling out any benefit the vitamin provided.

[Malila Robinson]

Martin,
Yes, expecting that because there was a general 40% lower chance of getting heart disease doesn't mean that everyone will get that exact benefit percentage. As you mentioned there may be other lifestyle choices that negate some of the benefits of the vitamin. But in general the vitamin should work to reduce heart disease to some extent, and in similar situations it should be around the 40% lower chance.

Malila

[martinbeslu]

So... the study shows that people who took XYZ had a 40% lower risk of heart disease. Are you saying that some people who took XYZ would only have a 30% lower risk and some people would have a 50% lower risk? What would that be based on? The study doesn't provide multiple risk percentages based on age, weight, gender, etc. All we know is that overall the risk is 40% lower. If someone who took XYZ got heart disease would we say that their risk was 100%? Even if they got the disease, wouldn't their risk still have been 40% lower based on what we know from the stimulus?

[Malila Robinson]

Hi Martin,
The study showed an average decline of 40%. So yes, the percentages that people within the experimental group experienced could be more or less than 40%. The stimulus does not specify what could cause the difference, but does state that health habits such as diet were taken into account. The things that you mentioned like age, weight, gender, etc. could have something to do with the variations.
As for your other question, it does not mean that if you get heart disease your risk percentage would bump up to 100%. It means that If your original risk factors said you were 100% likely to get heart disease and you took XYZ under circumstances that were similar to the experiment, your risk of heart disease should be reduced by around 40%, (so your risk factors would have decreased to around 60% due to XYZ).
Hope that helps!
-Malila

[ericj_williams]

Is it a Must Be True or a Most Strongly Supported?