Scientific method independent variable

An independent variable is the factor a researcher deliberately changes or compares to examine its relationship with an outcome. The dependent variable is the measured response.

How it works

A well-designed investigation also identifies controlled variables: conditions kept as consistent as possible. Clear operational definitions explain how each variable is changed or measured.

Example or application

To study how light affects seedling growth, a researcher could vary light exposure and measure growth over a fixed period while keeping soil, water, and seed type similar.

Scope and limits

Not every study manipulates a variable. Observational research may compare naturally occurring differences, so “independent variable” should be used in a way that fits the design.

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