From a Slate

Essay

From a Slate.com article entitled "Psych-Out Sexism: The Innocent,Unconscious Bias That Discourages Girls from Math and Science," published on March 1,2011.
Stout,Dasgupta,and their colleagues wanted to find out why women's outstanding performance on science and math tests in high school and college correlates so weakly with their eventual interest in pursuing careers in those fields.In high school and college,girls increasingly earn math and science grades equal to or better than the grades of their male peers.But when it comes to choosing a career in math or science,more men than women decide to walk through those open doors.
The psychologists asked female students studying biology,chemistry,and engineering to take a very tough math test.All the students were greeted by a senior math major who wore a T-shirt displaying Einstein's E = mc² equation.For some volunteers,the math major was male.For others,the math major was female.This tiny tweak made a difference: Women attempted more questions on the tough math test (comprising 10 questions)when they were greeted by a female math major rather than a male math major.


-In the study described above,name the variables and indicate the levels of each.