A Researcher Interested in the Effects of Test Anxiety on Math

A researcher interested in the effects of test anxiety on math test performance finds 40 volunteer students who report high levels of test anxiety.The researcher randomly assigns 20 of the students to a workshop on relaxation techniques and the other 20 students to a workshop on basic computer skills.After four weeks of classes,the researcher compares the average math test scores of the two groups to see which group has better scores.The independent variable in this study is ________ and the dependent variable is ________.

A) type of workshop; math test scores
B) length of the workshop; test anxiety
C) test anxiety; length of the workshops
D) math test scores; type of workshop