10.2 Overall Vocabulary

• variable: a quantity, quality, or property that you can measure.
• value: the state of a variable when you measure it. Can change.
• observation: a set of measurements made under similar conditions. One value per variable.
• tabular data: observations of variables.
• tidy data: 1 observation per row, 1 variable per column, 1 value per cell. Definition of “tidy” for a dataset can depend on what you’re trying to answer.