In statistics

Statistics

Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

, categorical data is that part of an observed dataset that consists of categorical variables, or for data that has been converted into that form, for example as grouped data

Grouped data

Grouped data is a statistical term used in data analysis. A raw dataset can be organized by constructing a table showing the frequency distribution of the variable...

. More specifically, categorical data may derive from either or both of observations made of qualitative data, where the observations are summarised as counts or cross tabulation

Cross tabulation

Cross tabulation is the process of creating a contingency table from the multivariate frequency distribution of statistical variables. Heavily used in survey research, cross tabulations can be produced by a range of statistical packages, including some that are specialised for the task. Survey...

s, or of quantitative data, where observations might be directly observed counts of events happening or they might counts of values that occur within given intervals. Often, purely categorical data are summarised in the form of a contingency table

Contingency table

In statistics, a contingency table is a type of table in a matrix format that displays the frequency distribution of the variables...

. However, particularly when considering data analysis, it is common to use the term "categorical data" to apply to data sets that, while containing some categorical variables, may also contain non-categorical variables.