Q. What is an inference?

The process of logical reasoning that combines observed phenomena with accepted truths or axioms in order to formulate generalizible statements. Statistical inference applies the process to data sets with calculated degrees of uncertainty. Causal inference, often applied to results of epidemiological research, is the process of logical reasoning that must often rely on accumulated circumstantial evidence to reach conclusions about cause-effect relationships.
---from Oxford Dictionary of Public Health

The process of moving from (possibly provisional) acceptance of some propositions, to acceptance of others. The goal of logic and of classical epistemology is to codify kinds of inference, and to provide principles for separating good from bad inferences.
---from Oxford Dictionary of Philosophy

The process of deducing properties of the underlying distribution by analysis of data.
---from Oxford Dictionary of Statistics