Next Section: Summation Notation

The word "statistics" is used in several different senses. In the broadest sense, "statistics" refers to a range of techniques and procedures for analyzing data, interpreting data, displaying data, and making decisions based on data. This is what courses in "statistics" generally cover.

In a second usage, a "statistic" is defined as a numerical quantity (such as the mean) calculated in a sample. Such statistics are used to estimate parameters.

The term "statistics" sometimes refers to calculated quantities regardless of whether or not they are from a sample. For example, one might ask about a baseball player's statistics and be referring to his or her batting average, runs batted in, number of home runs, etc. Or, "government statistics" can refer to any numerical indexes calculated by a governmental agency.

although the different meanings of "statistics" has the potential for confusion, a careful consideration of the context in which the word is used should make its intended meaning clear.

Next Section: Summation Notation