81. The variable the researcher matches to eliminate it as an alternative explanation is called a ___ variable.A. MatchingB. IndependentC. DependentD. Partial AnswerA. Matching 82. Which of the following is not a longitudinal design?A. PanelB. Cross-sectionalC. TrendD. Both a and c are longitudinal designs AnswerD. Both a and c are longitudinal designs 83. In qualitative…