Researcher was interested in the difference in aggressive behavior across grade levels. They selected 2 samples to compare: a group of 1st graders at a public school and a group of 5th graders from a private school. the researcher measured the # of times each child hit another during 30 min. playground interaction. The results showed no differences between 1st graders and 5th graders. The researcher concluded that there are no grade differences in aggressive behavior.
1.) What research design was used in this study?
2.) What is the independent variable in this study?
3.) what is the dependent variable in this study?