Verbal Lecture-06
INFERENCE QUESTIONS:
(Must Be True)
Inference questions test your ability to conclusively deduce certain other information from the information provided in the passage. These questions usually includes words: “If the information in the passage is true, what MUST also be true?”. For instance,
A is greater than B. And B is greater than C.
From this information, we can infer that A is greater than C.
Note that this inferred statement is MUST be true.
On other hand,
A is greater than B. And C is also greater than B.
From this information, we cannot inferred that A is greater than C. This statement COULD be true, but not MUST be true.
While you can often predict a close replica of the correct answer choice in a Strengthen or Weaken question, Inference questions are much more an exercise in process of elimination. The standard for a correct Inference answer is that it must be true. That means that an incorrect answer is not necessarily true—or, in other words, an incorrect answer could be false.
There are three major skills tested in such type of questions:
1. Your ability to comprehend the information given in the argument.
2. Your ability to identify the scope of the information.
3. Your ability to draw inference.
Remember that most of the arguments contains conclusion, but argument that asks inference question may or may not have conclusion. When there is no conclusion in the argument, then the correct answer of an inference question is the conclusion, which is also MUST be true statement.
Let’s consider some examples:
90% of the people in Arizona get flu shots every year. 15% of people in Arizona were treated for flu last year.
Which of the following can be inferred from the argument above?
I. Flu shots are not effective in Arizona.
II. People who get flue shots in Arizona do not fall sick with flu. Not true
III. Some people who get flu shots have to be treated for flu. True.
IV. Many people who fell sick with flu did not get flu shots. Not true.
V. Many people who got flu shots did not fall sick. True.
Answer Explanation:
Self-Analysis:
The argument contains some statistical information. So let’s say, there are 100 people in Arizona. 90 of the people get flu shots every year, while 15 people got sick with flue last year. So it means at least 5 people MUST get flue despite having flu shots. (Note: at least means minimum, i.e there may be all 15 people who get sick despite having flu shots).
Choice I: As this statement is not MUST be true, so this cannot be an inference statement. The effectiveness of flu shots is not defined, i.e whether 99% success rate means effective or 51% success rate is effective.
Choice II: This statement leaves no margin for people who get flu shots cannot fall sick with flu. But according to the argument, there are some people (i.e min 5 to max 15) who must got sick despite having flu shot. So this statement is not MUST be true and hence eliminated.
Choice III: This statement is clearly MUST be true, as min 5 people who get flue shots MUST be treated for flue, despite having flu shots. So this statement is correct inference.
Choice IV: This statement is also not a MUST be true statement. 15 people fell sick last year. But min 5 and max all 15 people MUST be treated for flu. As the statement include word “many”, which means greater than 50%. So there is a possibility that less than 50% people (i.e min 5 people) MUST be treated for flu despite having flu shots. Thus, this statement is not an inference.
Choice V: This statement is a MUST be true statement. As there are max (90 – 5) or min (90 – 15) people who got flue shots did not fall sick with flue. As there are more than 50% people, thus, this statement is also correct inference.
“Must be true” is a high standard of proof. Words like “all,” “only,” “and,” etc. are quite limiting, so pay attention to the parameters of each answer choice. If you can find an opportunity for even part of the conclusion to be false, that is your opportunity to eliminate it and move on. Consider an example:
If Shero wins the election, McGuinness will be appointed head of the planning commission. But Stauning is more qualified to head it since he is an architect who has been on the planning commission for 15 years. Unless the polls are grossly inaccurate, Shero will win.
Which one of the following can be properly inferred from the information above?
(A) If the polls are grossly inaccurate, someone more qualified than McGuinness will be appointed head of the planning commission.
(B) McGuinness will be appointed head of the planning commission only if the polls are a good indication of how the election will turn out.
(C) Either Shero will win the election or Stauning will be appointed head of the planning commission.
(D) McGuinness is not an architect and has not been on the planning commission for 15 years or more.
(E) If the polls are a good indication of how the election will turn out, someone less qualified than Stauning will be appointed head of the planning commission.
Answer Explanation:
This question provides an excellent illustration of the “must be true” Inference question standard. While the facts do show that Shero, if elected, will appoint a less-qualified planning commissioner, McGuinness, there is nothing explicit that says Stauning would even be considered under any other regime. You may think that Shero is the only person who would appoint McGuinness, but there is no evidence given for that. The only thing we know here is that a Shero win means that McGuinness, a lesser planning commissioner than Stauning, will be appointed. So while options like answer choice A (if Shero loses, a better commissioner will be appointed) and answer choice B (Shero is McGuinness’s only hope to get the job) may seem probable, they are not necessarily true.
On a question like this, you can eliminate incorrect answer choices by proposing hypothetical that are consistent with the facts but undermine the answer choice. To eliminate answer choices A, B, and C here the hypothetical “for some reason, anyone who wins will select McGuinness” undercuts all of those answer choices. Only answer choice E is necessarily true.
Focus on Scope:
As you learned in the last problem, scope is fundamentally important in determining whether an answer choice must be true in an Inference question. Correct, “must be true” answers stay within the scope of the information given in the stimulus; incorrect, “not necessarily true” answers go beyond the scope of the information given in the stimulus. Consider the following example and focus on staying within the scope of the argument at hand:
Treasure Hunter: In general, archaeological artifacts found on public property cannot legally be privately owned. But according to centuries-old maritime law, people who risk their lives attempting to rescue a ship in peril are permitted to keep whatever cargo they can salvage. Under this rule treasure hunters clearly are entitled to keep the cargo from ancient shipwrecks that they risk their lives
to save from oblivion in public waters.
Archaeologist: Not so. These shipwrecks have stabilized over the centuries they have lain underwater. The only danger they are in is from greedy treasure hunters who destroy archaeological evidence in their hurry to loot salable artifacts.
On the evidence of their statements, it can be concluded that the treasure hunter and the archaeologist disagree on which of the following?
(A) What constitutes an archaeological artifact
(B) In what sense, if any, an ancient shipwreck can be said to be in peril
(C) Whether treasure hunters risk their lives when they retrieve artifacts from ancient shipwrecks
(D) Whether maritime law can ever be applied to a ship that has already sunk
(E) Whether antique shipwrecks in public waters can properly be said to be on public property
Remember: The correct answer on an Inference question must be true. And the previous question provides an excellent example of that. The treasure hunter and archaeologist may well disagree on many grounds, but we can only answer the question based on what is explicitly in the passage. And the key to that lies with the archeologist’s rebuttal: “The only danger (these shipwrecks) are in is from greedy treasure hunters….” He chooses to rebut the claim that the ships are in any real danger, having already sunk long ago, meaning that he clearly disagrees with the assertion that they are in peril. Answer choice B, then, must be true.
Answer choice D, while it may seem clear as a point of disagreement in this case, is not necessarily true overall. It is simply too broad, as the argument as stated only pertains to ancient shipwrecks that have long since settled. To say that they necessarily disagree whether the law can “ever” apply to “any ship that has already sunk” ignores plenty of possibilities with recently sunk ships or other aspects of the maritime law code. Answer choice D makes the mistake of generalization, but does so by subtly drawing a broad conclusion to an argument in which narrow circumstances are given. Beware the overly broad conclusion in Inference questions.
Similarly,
Angela Merkel, the German Chancellor, has decided to suspend her earlier plans to extend the life of Germany’s nuclear power stations, after the nuclear emergency triggered by Japan’s devastating earthquake. After two hydrogen explosions at the Fukushima Daiichi reactor in Japan, Merkel decided to re-examine her highly controversial decision last year to renew the country’s 17 nuclear plants for an average 12 years.
Which of the following correctly inferred from the information above?
I. If Angela Merkel decision is not reversed, German seventeen nuclear plan would soon be shut down. Cannot imply from the passage.
II. Unless Merkel changes her position, the 17 nuclear reactor in Germany will reach their end of life as planned, if nothing unexpecting happens.
III. Nuclear power plan carry more risk to operate than traditional power plants do.
IV. Hydrogen explosion at Fukushima reactor in Japan have led many countries to re-consider their nuclear power plan.
V. Hydrogen explosion at Fukushima reactor has played a role in Angela Merkel decision to close the Germany reactor.
Inference vs Assumption:
There is a difference between inference statement and assumption. The similarity between the two statements is that both of these statements are MUST be true. But assumption statement is a statement on which the argument depends. If this statement is no more MUST be true, the argument cannot stand. On other hand an inference statement is a statement which depends on the argument.
Assumption question stem:
Which of the following MUST be true in order to make the conclusion to hold true?
Inference question stem:
If the information above is true, which of the following MUST also be true?
Notice that the assumption question portrays that ‘the argument depends on which of the following answer choice’. While inference question portrays that which of the following answer choice MUST be deduced from the information in the argument; i.e ‘which of the following choice depends on the argument above’.
Important takeaways:
While not as common as Strengthen and Weaken questions, Inference questions are nearly certain to show up multiple times on your exam. To succeed with Inference questions, remember these three critical themes:
• Make sure that you properly categorize Inference questions. It is easy to confuse them with Strengthen questions or assumption questions.
• Correct answer choices on Inference questions must be true. Regardless of how the question stem is worded, once you determine that the question is asking for a conclusion, make sure the conclusion you pick must be true.
• Scope is the key to success on Inference questions. Incorrect answer choices always go a little too far—that is, they go outside what can be guaranteed from the information in the stimulus. Be wary of broad, categorical statements that seem reasonable but are not supported by the information in the stimulus.