Michi is reading about a fictitious experiment in her psychology textbook, which is described as having one major flaw. the researcher had a treatment group and a control group, but the treatment group was led by a man and the control group was led by a woman. because the gender of the researcher was changing in sync with the independent variable, it is difficult to determine whether changes in the dependent variable were caused by the treatment or the gender of the researcher. thus, gender in this case is considered to be a(n): a. confounding variable. b. inferential statistic. c. hindsight bias. d. extraneous variable.