What is DATA? Data is a plural of datum, which is originally a Latin noun meaning "something given." Today, data is used in English both as a plural noun meaning "facts or pieces of information" and as a singular mass noun meaning "information".

Information refers to data being arranged and presented in a systematic or an organize form, so that some useful inferences can be drawn from the same. By data we generally mean quantities, figures, statistics, relating to any event.

CAT test writers use data sufficiency questions to test your ability to "reason quantitatively." This stands in sharp contrast to the problem solving section, which is designed to test how well you manipulate numbers. If you find yourself doing a lot of number crunching on the data sufficiency questions, you are doing something wrong.