### Explanatory Variable

- The
**explanatory variable (EV)** is the variable used to **explain or predict **another variable (the response variable). - By convention, the explanatory variable is plotted along the x-axis of a graph, if it is numerical.

### Response Variable

- The
**response variable (RV)** is the variable which is explained or predicted by the explanatory variable. - By convention, the response variable is plotted along the y-axis of a graph, if it is numerical.

Note: both explanatory and response variables can be either categorical or numerical variables.

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