The Mixed Model (MM) design, sometimes known as a Split-Plot design, is very popular in educational research. This model can be used to examine the effects of several independent variables on a dependent variable and it offers a more powerful alternative to the completely randomized design. The MM design considers both a between-subjects factor,…

The purpose of the present study was to examine and compare the effectiveness of pre-teaching and re-teaching on math achievement and academic self-concept of third grade students identified as low achievers. A pretest-posttest experimental design was used to conduct the study. Results indicated that both pre-teaching and re-teaching resulted in…