a type of regression model used to describe data and to explain the relationship between one dependent binary variable and one or more nominal, ordinal, interval or ratio-level independent variables.
used to describe data and to explain the relationship between one dependent binary variable and one or more nominal, ordinal, interval or ratio-level independent variables, for probability  e.g. exponential(.)/(1+exponential(.))
a set of data is categorical if values or observations belonging to it can be sorted into different categories