The analysis (see Table 6) shows that group membership had significant and medium size (Problem 2: F(1, 111)=12.5; p<0.01; ω2=0.10) up to large effects (Problem 3: F(1, 111)=22.5; p<0.01; ω2=0.16; Problem find more 5: F(1, 111)=36.0; p<0.01; ω2=0.23) on the achievement measures (total: F(1, 111)=29.3; p<0.01; ω2=0.20). Note that the largest values were obtained for problems with competence levels

above III (see Table 3a), which, according to their definition involve transfer of knowledge ( Baumert et al., 2002). Prior achievement in physics had significant but small influence on Problem 2 (F(1, 111)=6.6; p<0.05; ω2=0.05) and Problem 4 (F(1, 111)=4.6; p<0.05; ω2=0.04), a large influence on Problem 3 (F(1, 111)=29.8; p<0.01; ω2=0.32) and a medium size effect in total (F(1, 111)=19.5; p<0.01; ω2=0.12). For school type, gender and the

remaining covariates neither any main effect nor any interaction with group membership were found to be significant. Motivation was analyzed in a repeated measures design and ANCOVA with treatment groups (group membership (GM) vs. Belnacasan mw school type (ST) and gender (GR)) as between subjects factors and time of measurement (pre-, post- and follow-up-test; MOT1-PRE vs. MOT2-POST vs. MOT3-FUP) as a within subject factor. Non-verbal intelligence, reading comprehension and prior achievement in physics were used as covariates (see Table 4 and Table 7 for descriptive data on MOT1-PRE and MOT2-POST as well as MOT3-FUP, respectively). Between subject effects ( Table 8a): significant and – without exception – large main effects Chloroambucil of treatment group were found for overall motivation and all its subscales (classroom climate CC: F(1, 111)=119.6; p<0.01; ω2=0.45; self-concept SC: F(1, 111)=109.8; p<0.01; ω2=0.48;

intrinsic motivation in general IM: F(1, 111)=92.2; p<0.01; ω2=0.44; total: F(1, 111)=125.7; p<0.01; ω2=0.52). Significant but small up to medium sized effects were obtained for interactions of group membership with school type (GM×ST; CC: F(1, 111)=7.4; p<0.05; ω2=0.06; total: F(1, 111)=5.8; p<0.05; ω2=0.04) and with gender (GM×GR; total: F(1, 111)=4.9; p<0.01; ω2=0.04) for some subscales and in total measurement of motivation. Also the interaction of group membership with school type and gender became significant but only with small up to medium effects on two of three subscales and on total motivation measurement (GM×ST×GR; CC: F(1, 111)=7.9; p<0.05; ω2=0.07; IM: F(1, 111)=10.3; p<0.01; ω2=0.08; total: F(1, 111)=6.0; p<0.05; ω2=0.05). As for covariate influences, a significant medium resp. large influence of ‘prior achievement in physics’ on two of three subscales of motivation was obtained, viz. classroom climate (CC: F(1, 111)=9.7; p<0.05; ω2=0.08;) resp.