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June 2007, Logical Reasoning 1, Question 15


Question 15, which the following is an assumption that would allow the conclusion above to be properly drawn? Properly drawn, assumption, this is a sufficient assumption question. On a sufficient assumption question, our job is to find a new piece of evidence in the answer choices that when added to the evidence we've already been given in the stimulus will prove the conclusion that the stimulus draws absolutely true.

No doubts, no ifs, ands, buts, the conclusion is 100% true. So our first step, then, is gonna be to break the argument down to find its conclusion and take stock of the evidence that we have. They helpfully flag the conclusion with the word so. Every year it'll be necessary for all high-risk individuals to receive a vaccine for a different strain of the virus.

Now the evidence here has many parts. So the first sentence is just a little bit of setup information. It tells us that there is a new government policy that's goal is trying to avoid the flu. And they tell us how the goal is going to be accomplished by the annual vaccination of high-risk individuals.

And they even tell me who those individuals are, everyone 65 years and older, as well as everyone with a chronic disease that might cause them to experience complications from the flu virus. The real piece of evidence here is, each year's vaccine will protect only, pay attention to qualifying words like only, it's gonna protect only against the strain of influenza deemed most likely to be prevalent that year.

Now we think about the gap between the conclusion and the evidence. Each year the vaccine is only good against one strain, whichever one that they deem to be the most likely to be prevalent. So they say that means that every year you're going to need a different one. Well, the difference here, the gap is between that year and every year. So is it the case that every year we get a different strain of virus that's supposed to be prevalent?

Like say, the virus that was supposed to be the most prevalent in 2020 comes back in 2022. Would you still need a new vaccine for it? Well, no. It's effective against the one strain. So essentially, we've got to close down the loophole of the possibility of repeats.

Let's look at the answer choices. Answer choice A, the number of individuals in the high risk group for influenza will not significantly change from year to year. The number of people that we are immunizing isn't really an issue in the argument. They're giving it to every high-risk individual.

How many flu shots they need is not going to help us prove that they need a different strain of the virus or different vaccine every year. So B, the likelihood that a serious influenza epidemic will occur varies from year to year. How often we get a flu actually breaking out is irrelevant. This argument says, they give it out for the virus deemed most likely to be prevalent.

If there's a year where the virus doesn't actually show up, doesn't matter, they deemed one to be likely to be prevalent. B doesn't help us out. C, no vaccine for the influenza virus protects against more than one strain of the virus. Okay, well, this is helpful.

But we already know that the vaccine they are using is only gonna work against the strain that's deemed to be most prevalent that year. So this extends it out and say that there's not any other vaccines they could use. You're stuck with one vaccine, one virus. Still doesn't prove I need a different virus every year, and that's my job on this question.

We have to prove that we're gonna need a different virus, or that we're gonna need a different shot every year. Answer choice D, each year the strain of influenza virus deemed most likely to be prevalent will be one that had not previously been deemed to be most likely to be prevalent. So this is our loophole closer.

Each year it's not gonna be one that previously had been prevalent. So if you have to use a different vaccine for every virus, and the virus' never repeat, then you will have to use a different vaccine every year. Answer choice D is our answer. As always, glance down at E just to make sure. E says, each year's vaccine will have fewer side effects than the vaccine of the previous year.

Side effects are irrelevant to the argument. We're just trying to prove that you're gonna get a different vaccine, a different formulation every year. It'd be great if E were true. I mean, great for the people getting the flu vaccine, not great for the argument. But E doesn't help us get to the conclusion, so it's not the answer.

Thus, the answer is answer choice D.

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