Measure your independent variables carefully, and try to keep everything else the same.

The independent variables are the data collected in the survey.

A data point may consist of more than one independent variable.

In some cases, you may not be able to manipulate the independent variable.

This example has five independent variables and three fundamental units.

Explain the nature of independent variables and why this assumption is made.

We wonder if or how it is affected by the independent variable.

The independent variable on which one has to focus is the political culture.

In our car example, the independent variable is the shape of the car's body.

If you're interested in the lead of one over the other then you have to be more wary because they aren't independent variables.