An inference is a conclusion or opinion that is formed based on known facts or evidence. It is a process of deduction that involves using existing information to make educated guesses about missing pieces of information. Inference is theoretically divided into deduction and induction, with deduction being the process of reasoning from one proposition, statement, or judgment considered as true to another whose truth is believed to follow from that of the former, and induction being the process by which a conclusion is inferred from multiple observations. Inference is studied in various fields, including logic, argumentation studies, cognitive psychology, and artificial intelligence. Statistical inference uses mathematics to draw conclusions in the presence of uncertainty, and it uses quantitative or qualitative (categorical) data which may be subject to random variations.

Examples of inferences include:

• If you notice someone making a disgusted face after they’ve taken a bite of their lunch, you can infer that they do not like it.
• If a friend walks by with a graded test in her hand and a smile on her face, you could infer that she got a good grade on the test.
• If you see a woman pushing a baby stroller down the sidewalk, you can infer that there is a baby in the stroller.

Making inferences is an important skill in reading comprehension and critical thinking. It involves using observations and experience to connect clues and ideas and come to a conclusion.