LSAT 70, Logical Reasoning II, Q4

QUESTION TEXT: Physician: Stories of people developing serious health …

QUESTION TYPE: Strengthen

CONCLUSION: We shouldn’t be concerned by stories about people getting sick after vaccination.

REASONING: Millions of people get vaccinated every year. We can expect that some will get sick afterwards by coincidence.

ANALYSIS: The doctor has shown that the illnesses could be caused by coincidence. To strengthen his argument, we should show evidence that helps prove that the illnesses are due only to coincidence.

The right answer does this by showing that there is no increased risk of illness following vaccination. That’s pretty convincing.

___________

1. This may weaken the argument. If illness only follows new vaccines, then maybe the vaccines weren’t properly tested and they do cause illness.
2. This tells us whether or not to vaccinate people. It doesn’t show whether vaccines are safe.
3. CORRECT. Suppose this wasn’t true. Imagine 50 people a day get sick on average, but 600 people get sick the day after being vaccinated. That would imply that vaccines do increase risk. This answer eliminates that scenario – 50 people a day get sick the day before vaccinations, and 50 the day after. There’s no obvious increased risk.
4. This doesn’t tell us whether or not the vaccines caused the health problems.
5. If anything, this answer shows that vaccines can be dangerous. They make at least a few people sick. We’re trying to prove that vaccines don’t make people sick!

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