In the hypothesis, "the greater the availability of math tutoring, the higher the math grades," which would be the independent variable?

Availability of math tutoring.

Explanation:

In research, we have two different types of variables:

The independent variable is the one that the researchers can control and that will have an effect on another variable. The dependent variable is the one that cannot be control and that is affected by the independent variable. Researchers observe this variable to see how it changes. This is the variable that will be tested or measured.

In this example, the hypothesis is "the greater the availability of math tutoring, the higher the math grades". In other words, the tutoring will affect the math grades of the student. The researchers can control how much tutoring one student get but they cannot control what the grades will be and they will observe the grades to see how it changes depending on the amount of tutoring.

Therefore, the independent variable, the one that will affect the other one, is the availability of math tutoring.