Joanna is conducting a research project that examines whether parent’s income impacts a child’s choice of college. Joanna thinks that parents who make a lot of money will have children who will attend private schools and parents who make little money will have children who will attend public schools. ""Parent’s income"" is the in Joanna’s project.

Independent Variable.

Explanation:

As the exercise presents, the "Parent's income" is the independent variable in Joanna's project. An independent variable is, then, a variable that is changed or controlled in a scientific experiment, the variables that the experimenter changes to test it. Therefore, in Joanna's experiment that examines whether parent’s income impacts a child’s choice of college, Joanna thinks that parents who make a lot of money will have children who will attend private schools and parents who make little money will have children who will attend public schools. The "Parent's income" is, in fact, the independent variable given that it's the variable that is being controlled by her.