On the GRE, inference questions test your ability to understand and identify what a passage implies rather than what it explicitly states. But as with all RC questions, the answer must be squarely rooted in the text. Although you're making the inference, it is the text that is doing the implication.
The rationale for the inference must be unequivocally in the text. This question type asks you to take what’s on the page and extend or apply it with the fewest possible assumptions. The answer to an inference question must be something that follows logically from the text and which, given the information in the text, cannot be debated.
How to Identify an Inference Question-Type:
Inference questions tend to come in forms similar to these:
“This passage most likely appeared as part of . . .”
“The author would probably agree (or disagree) with which of the following statements?”
“This article most likely appeared in . . .”
“The author implies that the best control for unlicensed handguns would be . . .”
“Which of the following might the author cite as an example of free trade as it is described in the passage?”
“Given the author’s position on the fluoridation of the public water supply what stand would the author probably take on the issue of mandatory immunizations?”