Visualizing Quantitative Data

Synonyms

Graphics for continuous data; Visual displays of numerical data; Visualizing quantitative data

Definition

Quantitative data are data that can be measured on a numerical scale. Examples of such data are length, height, volume, speed, temperature, or cost.

A quantitative variable can be transformed into a categorical variable by grouping, for example, weight can be divided into underweight, normal weight, and overweight. The inverse transformation may not be possible.

Quantitative data can be categorical or continuous. This entry only concentrates on continuous data. Visualization in general means the graphical or visual display of data or relations.

Key Points

Univariate graphics are the most basic ones and display exactly one variable. There are three plot types that are commonly used: dotplots, boxplots, and histograms.

Dotplots draw every data point along one axis. This graphic shows clusters and gaps in the data. Overplotting can be a serious problem, because many points...