Katarina Is Interested in Attention Deficit Disorder and Behavioral Problems

Multiple Choice

Katarina is interested in attention deficit disorder and behavioral problems in school but believes that subjects' socioeconomic statuses may affect her results. So she is studying two groups of children in an intervention treatment, and makes sure each child in one group comes from a home with the same level of income as each child in the other group. What technique is this?

A) matched samples
B) matched pairs
C) random sampling
D) third-variable correlation