#14 - The "suicide wave" that followed the United States

[Administrator]

Complete Question Explanation

Weaken. The correct answer choice is (C)

In this stimulus, the author provides limited information from which an overly broad conclusion (that "the suicide wave... is more legend than fact") is drawn. The author compares the number of suicides after the crash to those from the previous summer, when the stock market was flourishing. Because the number of suicides after the crash was actually lower than it had been during the previous summer, the author concludes that the stock market crash did not in fact lead people to suicide.

The problem is that the information provided gives us only a small piece of the puzzle. For example, if suicides in winter are less common than suicides in summer, then the author's conclusion may not be valid. For a more accurate assessment, we may wish to compare the suicide figures of October 1929 to those of previous Octobers.

Answer choice (A): The many factors that affect the suicide rate in general are irrelevant to the author's question of whether the crash of '29 caused an increase in suicides.

Answer choice (B): This choice strengthens the argument: If we could normally expect to see high suicide rates during October, then the fact that the rates of October 1929 were lower than those of the preceding summer suggests that the author may be right.

Answer choice (C): This is the correct answer choice. If during the weeks following the crash there were many more suicides than we might normally expect to see during that time of the year, then this weakens the argument by making it more likely that some of those suicides were attributable to the crash.

Answer choice (D): Like incorrect answer choice (B) above, this answer choice strengthens the argument, because it would lead us to expect rates in October to be higher—not lower—than those of the preceding summer.

Answer choice (E): Without specifics, the mere fact that we should expect to see some seasonal variation in suicide rates has no effect on the author's argument. Should we normally expect higher rates in October than in the summer, or lower? The information provided in this answer choice provides no insight into the credibility of the author's argument.

[sdb606]

I mechanically eliminated A-D because they used "rate" instead of "number" like the stimulus. Do you have a good rule of thumb for when it's ok to select an answer that uses "rate" and not "number" for a stimulus that uses "number" and not "rate?" I just assume you cannot mix and match the two.

[Jeremy Press]

Hi sdb,

I'm not sure I can give you a handy rule of thumb that's going to cover all the contingencies in this scenario. As you discovered here, rate answer choices are not necessarily irrelevant to a stimulus that's using pure numerical data. So you want to get rid of that assumption.

Why is rate relevant here? It's relevant here because the stimulus relies on an improper numerical comparison. Comparing numerical data from the months of October/November in 1929 to numerical data from the summer months of the same year is improper, because there might be differences in the summer months that would lead us to expect the number of summer month suicides to be (ordinarily) higher (and maybe the summer month suicides are ordinarily MUCH higher, a degree of comparison the stimulus doesn't tell us about). What we could use, then, is an answer choice that potentially reveals that improper comparison, and that lets us compare apples to apples (October and November of 1929 to October and November of other years). That's answer choice C.

What does that tell me going forward? It tells me that if numerical data are used in an improper framework for comparison, information about rate changes that take place within the proper framework for comparison could be relevant.

I hope this helps!