Descriptive statistics - field that focuses on summarising or characterising a set of data. Inferential statistics - information from a sample to draw a conclusion about a population. Categorical (qualitative) data - can only be named or categorised. e. g. gender. Nominal data - no natural or implied order. e. g. bus, train, car. Ordinal data - implied order. e. g. good, bad, very bad. Numerical (quantitative) data - measured on a natural numerical scale. e. g. age. Continuous data - data that can take on any real number. Discrete data - countable number of responses (finite) Interval data - difference between measurements but no true zero. Ratio data - differences between measurements true zero exists. Time series data - data collected through time. Cross sectional data - collected from a point in time. Frequency distribution - summary table for numerical data. Class width - distance between upper and lower boundaries of a class.