Logical reasoning PrepTest 153 · Section 3 · Question 6

Incorrect. This would strengthen the argument. Not only did it work better than soliciting first time donors, the regular donors' program worked well enough to substantially increase supply.

Incorrect. "Proportionally" fewer doesn't matter very much here, as long as there are still enough regular donors in absolute terms to give the study an adequate sample size. If there were only two blood donors studied, that could be a problem. But this sounds more like "10% of donors were regulars vs. 15% in Pulaski," which wouldn't hurt the relevance of the study.

Incorrect. This would tend to strengthen the argument that this was an effective as well as cost-effective strategy. They didn't need to repeat the message over and over to keep their donors giving regularly.

Incorrect. Not necessarily a problem for the argument. If you have 50,000 sporadic donors and 5,000 regulars, but you can convince 50% of the regulars (2,500 donors) and only 2% of the sporadic donors (1,000 donors) to give more often, the regulars are still the better target.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
The best way to get more donated blood in Pulaski is to convince regular blood donors to give more often. A study conducted in other cities found it was hard to attract first-time blood donors, but comparatively easy and cost-effective to get regular blood donors to donate more frequently.

Answer Anticipation:
The biggest unanswered question here is "Is Pulaski's pool of existing blood donors pretty much the same as the other cities' blood donor pools?" (Apologies for the "blood/pools" language in this paragraph.) If Pulaski doesn't have enough regular blood donors to increase the blood supply by giving more often, or if all the regulars already give as often as possible, the tactics that worked elsewhere won't work here. Expect to hear that one of those things is true, which would weaken the argument.

Answer Explanation:
Finally! Yes, if the Pulaski regulars can't give blood more often, there's no point in targeting them with a campaign asking them to donate more frequently. Unless Pulaski is trying to kill off its blood donors, which would be a creepy way to increase the blood supply . . . .

Key Takeaway:
Whenever we're drawing conclusions on the basis of a study, we've got to ask a few questions. Is the study relevant to the topic? Is the population studied similar to the population we're drawing conclusions about? Was the study biased? Was the sample size large enough? Don't trust studies automatically—they have to be relevant, and properly conducted.