Research Design
A nonequivalent control group design was used in this study. The level of significance (alpha) was set at 0.05. A pretest was administered to all subjects prior to the treatment. The pretest was helpful in assessing students' prior knowledge of dc circuits and also in testing initial equivalence among groups. A posttest was administered to measure treatment effects. The total treatment lasted for 95 minutes. In order to avoid the problem of the students becoming "test- wise", the pretest and posttest were not parallel forms of the same test.