"Surprising" Phenomenon
The group using mite-proof bedding reported no reduction in allergy symptoms despite the fact that the dust-mite allergens in their mattresses decreased by 69%.
Objective
The right answer will either show how a 69% reduction in mattress dust-mite allergens could have no impact on people’s symptoms, or explain that the participants’ reports inaccurately downplayed a symptom reduction that did occur.
A
Dust-mite allergens in bedding tend to irritate many allergy sufferers’ nasal passages more than do the same allergens in other locations, such as carpets.
This does the opposite of what we need. If bedding tends to be the dust-mite location that most irritates allergy sufferers, we would expect a 69% reduction in mattress allergens to lead to a decrease in allergy symptoms. We want something that shows why that didn’t happen here.
B
When people report their own allergy symptoms, they tend to exaggerate the severity of those symptoms.
Even if the allergy sufferers exaggerated the severity of their symptoms, they would have done so both before and after the study, meaning we would still expect the reports to show a change due to the decreased allergen exposure. This answer doesn’t explain why that didn’t occur.
C
The medical community does not fully understand how dust-mite allergens cause allergy.
In order for this to be the right answer, we would need some indication that the information the medical community is missing would explain why the allergy sufferers in the experiment did not experience a reduction in symptoms. Because this doesn’t give us that, it’s not helpful.
D
For dust-mite allergy sufferers to get relief from their allergies, dust-mite allergens must be reduced by 90 to 95 percent.
This explains why the participants in the study did not experience a reduction in their allergy symptoms: their exposure to allergens did not decrease enough to lead to symptom relief.
E
All of the participants in the study were told that one group in the study would be sleeping on mite-proof bedding.
This doesn’t help us. Many studies are structured this way; as long as participants are unaware of which group they are in, we wouldn’t expect a placebo effect to skew the reports of allergy symptoms.
Note: This is video #2 in a two-part explanation using the split approach for comparative passages. In the previous video, J.Y. already tackled whatever questions he could based solely on a readthrough of Passage A. In this video, he picks up with Passage B and then cleans up the remaining questions. So, if you don't see a full explanation for a given question in this video, it's because J.Y. tackled that question in the previous video. (Press shift + ← to head to the previous video.)
Note: This video deals with Passage A only. In this video, J.Y. uses the split approach for comparrative passages. This means he reads through Passage A and then makes a first pass through the questions, answering them to the extent possible based solely on the information in Passage A. For an explanation of Passage B and the remaining unsolved questions, head to the next video (shift + → on your keyboard).