MTTC 103 Elementary Practice Exam 2025 – Complete Study Guide

An independent variable is a factor that is manipulated or changed in an experiment to observe its effects on a dependent variable. In scientific research, the independent variable is what the researcher controls or alters to test how it influences other variables.

The description of the independent variable as the dosage and timing of an anti-inflammatory drug clearly illustrates its role in a controlled study. By changing the dosage or the timing of administration, researchers aim to observe the effects on health outcomes, which could be the dependent variable (like the reduction of inflammation or pain level).

In the other scenarios, the amount of paint relates to a practical task rather than an experimental variable, while the number of errors on a test is more of a result rather than something manipulated. Finally, the time it takes to drive between cities is dependent on many variables (like traffic and speed), making it more of a consistent outcome rather than an independent variable in a scientific context.