Over the last 10 years, there

Answer choices

1. A

   Correct48% picked this

   The number of people in the region under the age of 18 has increased over

   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%
2. B

   Weakens22% picked this

   The birth rate for the region decreased significantly over the last

   This provides the Alternate Explanation of "fewer young people". A strengthen answer would rule out an Alternate Explanation.

   22%
3. C

   Weakens, if anything5% picked this

   The total number of people living in the region has decreased over the

   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%
4. D

   Too Weak21% picked this

   The number of people who moved into the region over the last 10 years is greater than the number

   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%
5. E

   No Impact5% picked this

   The average age for people in the region is higher than that for people

   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.

   5%