Basic Data
Visualization

One Variable

Continuous

Categorical / Discrete

Histogram

Barplot

Two Variables

Explanatory: Categorical
Response: Categorical

Stacked barplot

Side-by-side barplot

Faceted barplot (usually preferred)

Explanatory: Categorical
Response: Numerical

Boxplot

Faceted histogram

Explanatory: Continuous
Response: Numerical

Multiple response values
per explanatory value

Single response value
per explanatory value

Scatterplot

Line-graph

Note that Explanatory corresponds to the Independent variable and Response corresponds to the Dependent variable.

Stacked proportional barplot