In an experiment examining the effects Tai Chi on arthritis pain, Callahan (2009) selected a large sample of individuals with doctor-diagnosed arthritis.
Half of the participants immediately began a Tai Chi course and the other half (the control group) waited 8 weeks before beginning the program. At the end of 8 weeks, the individuals who had experienced Tai Chi had less arthritis pain that those who had not participated in the course.
a. Identify the independent variable for this study.
b. What scale of measurement is used for the independent variable?
c. Identify the dependent variable for this study.
d. What scale of measurement is used for the dependent variable?