Logical Reasoning

PT119 · S3 · Q22 Over the last 10 years, there

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Over the last 10 years, there has been a dramatic increase in the number of people over the age of 65 living in this region.

Conclusion

In this region, over the past 10 years, the number of people over 65 has gone way up.

Evidence

In this region, over the past 10 years, the average age has gone from 52 to 57.

Evaluate

It's not a gimme that people sort out which claim is the Conclusion vs. Evidence, so let's acknowledge the importance of understanding this is evident from the fact that.

Claim 1. This is evident from the fact that Claim 2.

Which claim is being supported by the other? Which claim is opinion, which is fact?

Claim 2 is being called a fact, so Claim 1 has to be the opinion. Why should we believe claim 1? Well, it's evident from the fact that Claim 2!

Because the author is interpreting a statistic/study, we can use our Curious Fact / Explanation mindset.

Curious Fact Why has the average age gone from 52 to 57?

Author's Explanation There are a lot more people over 65 living in the region now.

The two pressure points we always consider: - alternate explanations for the Curious Fact - plausibility of the Author's Explanation

What else could cause an average age to go from 52 to 57?

If you want an average to move up, then you either add higher numbers to the data set, or you remove lower numbers from the data set.

If a bunch of young people left the region, the remaining pool of people would have a higher average age, even with the same number of people over 65.

It's also possible that the average went from 52 to 57 because there a lot more 57-65 year olds. Adding people of those ages could lift an average from 52 to 57 (though there would have to be a lot of them to do so).

Is there any plausibility to the storyline that there are a lot more people over 65? Has there been an increase in retirement communities, senior events, or pigeon-feeding? (had to take a cheap shot).

Goal

Because this is Strengthen, the correct answer should either rule out an Alternate Explanation or add plausibility to the Author's Explanation

So we're looking for ruling out "fewer young people" or "more people from 57-65".

Or we want an answer that adds some plausibility to the story that the region has lots more citizens over 65 nowadays.

22.

Which one of the following, if true, would most strengthen the argument?

Correct
The number of people in
Why this is right
The author was trying to explain why the average age went from 52 to 57. The author assumes it changed because of more older people. But the average may have changed because of fewer young people. This answer strengthens by ruling out the possibility of that Alternate Explanation. (Mathematically, it also argues against the Alternate Explanation of "more people 57-65". It doesn't need to do that, for it to be correct. But it does. If the average age is 52 and you add someone 18 years old (34 below average), you would need to add someone 86 years old (34 above average), just to keep the average at 52. This answer is saying there are more people nowadays under 18. All other things being equal, those people would bring the average age down from 52. Since we know that the average not only didn't go down, it actually went up to 57, there have to be a lot of seniors added to the mix to balance out the effect of those added juniors and then increase the average from there.)
Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.
48% picked this
The birth rate for the
Weakens
This provides the Alternate Explanation of "fewer young people". A strengthen answer would rule out an Alternate Explanation.
21% picked this
The total number of people
Weakens, if anything
This fact doesn't give us any demographic comparison between young people vs. old people, in terms of which age group accounts more for the decrease. But on the face of it, a reduced population makes it somewhat less likely that there are "more people over the age of 65". All other things being equal, it makes it less likely that any age group has more people than 10 years ago.
5% picked this
The number of people who
Too Weak
This strengthens in the sense that if people moved in > people moved out then there was a net gain in population (all other things being equal). But it doesn't indicate it was a big gain in population, and we're working with a conclusion that says "there is a dramatic increase in people over 65". And this answer doesn't say anything specific to age group, so it doesn't give us any reason to think that whatever population increase did occur was primarily in the over 65 year old range.
21% picked this
The average age for people
No Impact
The average age of any other region is irrelevant, unless we're being told that people came from that region into the one we care about.
4% picked this

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