Dependent and Independent Variables
Independent Variable: a variable manipulated in an experiment in order to observe the effect on a response variable
Dependent Variable: response variable, a variable that is dependent on independent variable(s)
ex: A tutor wants to investigate the effect of revision time and intelligence on the test performance of 100 students. The dependent variable is test score, and the independent variables are revision time and intelligence.
Categorical and Continuous Variables
Continuous Variable: has an infinite number of possible values
ex: temperature, height
Categorical Variable: has a finite number of possible values
Categorical variables can be
- nominal: 2 or more categories without order
ex: language (English, French, Spanish...)
- binary (dichotomous): only 2 categories
ex: gender (male, female)
or
- ordinal: 2 or more categories with order
ex: economic status (low, medium, high)
