*Quantitative data/**Quantitative **variables*: Information that can be handled numerically.

*Qualitative data/**Qualitative **variables*: Information that refers to the quality of something. Ethnographic research, participant observation, open-ended interviews, etc., may collect qualitative data. Some element of the results obtained via qualitative research may be handled numerically, eg, how many observations, number of interviews, etc.

*Time series data*: Any data arranged in chronological order.

*Longitudinal data*: data that is collected repeatedly over a period of time, in which the same group of respondents are surveyed each time.

**Discrete data**: numeric data that have a finite number of possible values (1,2,3,4,5)

*Continuous data: *data that has an infinite number of possible values (1.4, 1.41, 1.414, etc.)

**Levels of Measurement**

*Nominal*: Nominal data have no order and only gives names or labels to various categories (yellow, white, pink).

**Ordinal**: Ordinal data have order, but the interval between measurements is not meaningful (low, medium, high).

*Interval*: Interval data have meaningful intervals between measurements, but there is no true starting point (Fahrenheit temperature scale).

*Ratio*: Ratio data have the highest level of measurement. Ratios between measurements as well as intervals are meaningful because there is a starting point (Kelvin temperature scale).