Data Table
A rectangular arrangement of data, as in a spreadsheet. Rows and columns carry specific meaning
Observation
Names given to the rows in a data table
Variable
A column in a data table that holds a common attribute of the cases
Categorical variable
Column of values in a data table that identifies cases with a common attribute
Numerical variable
Column of values in a data table that records numerical properties of cases (also called continuous variable)
Measurement unit
Scale that defines the meaning of numerical data, such as weights measured in kilograms or purchases measured in dollars
Ordinal variable
A categorical variable whose labels have a natural order
Likert scale
A measurement scale that produces ordinal data, typically with 5 to 7 categories
Recode
To build a new variable from another, such as by combining several distinct values into one
Aggregate
To reduce the number of rows in a data table by counting or summing values within categories
Time series
A sequence of data recorded over time
Time plot
A graph of a time series showing the values in chronological order
Frequency
The time spacing of data recorded in a time series
Cross-sectional data
Data that measure attributes of different objects observed at the same time