Defining data

On watching this video, students should be able to:

1. Classify variables as either numerical or categorical. If a variable is numerical, then further classify as either a continuous or discrete. If a variable is categorical, then further classify as ordinal or nominal. 
2. Explain what is meant by unit of observation.
3. Classify variables with respect to their contextual use in a study as either an exposure or an outcome variable, and be able to identify other terms that are often used interchangeably, these include, dependent and independent variable, Y and X variables, response and explanatory variables.