Medical researchers studying a medication in male and female patients 20 to 29 years old noticed that, up to a certain amount, a larger concentration of an active ingredient lead to greater levels of symptom relief. What is the explanatory variable?

The explanatory variable is the factor researchers use to explain or predict changes in another variable. Here, the researchers noticed that symptom relief increased as the concentration of the active ingredient increased, so concentration is the explanatory variable. The amount of symptom relief is the response variable.

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