Overview: Inference | Verbal for GMAT PDF Download

Introduction

In Inference Questions, unlike typical Critical Reasoning scenarios where there is both a premise and a conclusion, the argument is built solely on-premises. These questions don't provide a conclusion outright; instead, the question prompt requires you to draw a conclusion based on the given premises. You can recognize these questions by the use of terms like conclude, conclusion, infer, or inference in the question stem.

Here are a few examples of inference questions:

1. The statements above, if true, best support which of the following as a conclusion?
2. Which of the following inferences is best supported by the statement made above?
3. Which of the following conclusions can most properly be drawn from the information above?
4. If the statements above are true, which of the following must be true?

It's crucial to emphasize that the right answer choice for Inference Questions takes a small, logical step beyond the given premises. The inference should be a modest progression, avoiding assumptions, and directly stemming from the provided information. Additionally, the correct answer should mirror the tone (positive, negative, neutral) expressed in the argument.

What does Inference Mean?

The term "infer" is quite versatile. In everyday language, it often means making an educated guess. For instance, if your friend Jane mentions she avoids hot fudge sundaes, you might use your knowledge to guess her reasons. However, on the GMAT, "inference" takes on a more specific meaning. Here, inferring is about logically deducing consequences from assumed premises.

How to Solve

On the GMAT, when you learn that Jane doesn't eat hot fudge sundaes, two logical consequences follow:

If Jane eats something, it's not a hot fudge sundae.

If someone eats a hot fudge sundae, it's not Jane.

The correct answer to an inference question on the GMAT stems directly from the provided evidence; it's not a mere guess but a logical result of the assumed premises.

It's essential to note that even a brief statement like "Jane doesn't eat hot fudge sundaes" can lead to multiple inferences. Considering the volume of information in an average GMAT question, predicting inferences becomes challenging. Thus, rather than guessing, the recommended approach is to use process of elimination, ruling out choices that are mere guesses, not necessarily true, overly extreme, or irrelevant. The correct answer will be the one that logically follows from the given statements.

Examples

Q1: In a recent press conference, the government promised the citizens of Town Y that the new national highway will not pass through existing archaeological heritage sites neighboring Town Y, including Site Z. However, the new highway will pass within a mile of Site Z, which is situated at the center of an area rich in archaeological sites yet to be completely discovered.
Which of the following inferences is best supported by the statements made above?
(A) The government has broken its promise to the citizens of Town Y.
(B) The citizens of Town Y are worried that the noise the new highway will generate might discourage tourists from visiting Site Z.
(C) Unless the national highway plan is changed, undiscovered archaeological sites will possibly be damaged during the highway’s construction.
(D) Now that the government has shown its commitment to preserving archaeological heritage sites, there is no longer a threat to Site Z or to whatever undiscovered archaeological sites there are in its vicinity.
(E) It is not that important if the area around Site Z is damaged by the highway since interest in archaeology is decreasing and the site would not receive many visitors anyway.

Let's evaluate the answer choices:

(A) This contradicts the first premise that the government assured the highway wouldn't go through existing archaeological sites. Since it's going through an area with undiscovered sites, it doesn't break the promise.
(B) Introduces a new concern without support from existing premises, making it an invalid conclusion.
(C) Aligns logically with the argument's premises. Given the presence of undiscovered sites around Site Z, and the highway passing nearby, it's reasonable to infer potential damage to these sites. Answer C seems correct, but let's review all choices.
(D) Based solely on premise A about the government's promise not to endanger Site Z, but premise B contradicts it, revealing potential danger to other sites.
(E) Requires significant assumptions and goes beyond the provided information. After careful consideration, it's evident that C is the most suitable answer, aligning with the argument's premises.

Q2: A recent study published in the Journal of Modern Nutrition revealed that consuming foods rich in Omega-3 fatty acids, like fish and nuts, correlates with improved cognitive function in adults over 50. The study followed a group of 1,000 individuals over a period of five years, regularly assessing their diet and performing cognitive tests. Notably, participants who regularly included Omega-3 rich foods in their diet consistently outperformed those who did not on cognitive tests.
Which of the following inferences is best supported by the statements made above?
(A) Consuming Omega-3 supplements is as beneficial for cognitive function as consuming Omega-3 rich foods.
(B) Cognitive decline in adults over 50 can be entirely prevented by consuming Omega-3 rich foods.
(C) Adults who consume Omega-3 rich foods are likely to have better cognitive function than those who do not.
(D) The improved cognitive function observed in the study is primarily due to factors other than diet, such as genetics or exercise.
(E) The majority of adults over 50 are not aware of the benefits of Omega-3 rich foods on cognitive function.
Sol: 
The study specifically correlates the consumption of Omega-3 rich foods with improved cognitive function in adults over 50. Based on this, the most direct and supported inference is:
(C) This option directly aligns with the findings of the study. It states that adults who consume Omega-3 rich foods are likely to have better cognitive function than those who do not, which is a reasonable inference from the study's results.
(A) The study does not provide information about Omega-3 supplements, so this inference goes beyond the available evidence.
(B) The study suggests a correlation, not a causal relationship that guarantees prevention of cognitive decline. Thus, this option overstates the findings.
(D) The statement doesn't provide information about other factors like genetics or exercise. Inferring that these play a primary role is unsupported by the study's findings.
(E) The study's findings do not include information about the awareness level of adults over 50 regarding the benefits of Omega-3 rich foods.

Therefore, the correct inference, based on the given information, is (C).

Q3: A recent survey conducted in the city of Greenfield showed that 60% of the population prefers public transport over private vehicles for their daily commute. The survey also highlighted that the city's public transport system has seen a 30% increase in ridership over the past year. Greenfield has been actively investing in improving its public transportation infrastructure, including expanding bus routes and introducing more frequent service.
Which of the following inferences is best supported by the statements made above?
(A) Most people in Greenfield use public transport because it is more economical than owning a private vehicle.
(B) The increase in public transport ridership is solely due to the recent improvements made by the city.
(C) If Greenfield continues to improve its public transportation infrastructure, the number of private vehicle users will decrease significantly.
(D) The residents of Greenfield are generally satisfied with the public transport system in the city.
(E) The preference for public transport in Greenfield is likely influenced by environmental concerns among its population.
Sol:
The survey results and the increased ridership indicate a positive trend towards public transport in Greenfield, especially following the city's infrastructure improvements. Evaluating the options:
(A) While economic reasons might be a factor, the survey data does not specifically mention the economy as the primary reason for the preference, making this inference somewhat speculative.
(B) The statement suggests a correlation between improvements and increased ridership, but asserting it as the sole reason is an overextension without further data.
(C) This is a plausible prediction based on the trend, but it's speculative to conclude the extent of the decrease in private vehicle use without more specific data.
(D) The preference for public transport and increased ridership could suggest satisfaction, but the survey does not explicitly measure satisfaction levels, making this inference a bit indirect.
(E) The survey and ridership data do not directly mention environmental concerns, so this inference, while possible, is not directly supported by the statements.

Based on the given information, (D) seems to be the most supported inference. It reasonably suggests that the preference for public transport and the increase in ridership are indicators of the residents' general satisfaction with the public transport system, even though it does not provide a direct measure of satisfaction.