Observing populations and testing predictions about genetic drift in a computer simulation improves college students’ conceptual understanding

Table 4 Summary of statistical tests used

Question motivating the model	Model	Predictor	Estimate ± SE	p value	Result
Do the students in the two treatments perform differently before instruction?	pretest performance ~ treatment + course + OLRE	Intercept	0.13 ± 0.17	0.427	No. The students in the two treatments did not differ in pretest performance
	pretest performance ~ treatment + course + OLRE	Treatment	0.32 ± 0.19	0.094
Does treatment predict posttest performance (controlling for pretest raw score)?	posttest performance ~ pretest raw score + treatment + course + OLRE	Intercept	−1.19 ± 0.23	<0.001	Yes. The students in the module courses outperformed students in the control courses
		Pretest	0.11 ± 0.01	<0.001
		Treatment	0.83 ± 0.24	<0.001
Does treatment predict performance on items about key concepts (controlling for pretest raw score)?	posttest_KC performance ~ pretest_KC raw score + treatment + course + OLRE	Intercept	−0.69 ± 0.33	0.036	Yes. Students in the module courses outperformed students in the control courses
		Pretest_KC	0.09 ± 0.03	<0.001
		Treatment	1.92 ± 0.35	<0.001
Does treatment predict performance on items about misconceptions (controlling for pretest raw score)?	posttest_M performance ~ pretest_M raw score + treatment + course + OLRE	Intercept	−1.08 ± 0.26	<0.001	Yes. Students in the module courses outperformed students in the control courses
		Pretest_M	0.17 ± 0.01	<0.001
		Treatment	0.56 ± 0.24	0.018

In all models, Course is a random factor that accounts for differences across classes that were not controlled during the study. Observation-level random effect (OLRE) is a random factor that accounts for overdispersion in the model. Subscript KC indicates the subset of items in the GeDI about key concepts; subscript M indicates the subset of items on the GeDI about misconceptions. Significant results after Holm-Bonferroni corrections are in italics

ISSN: 1936-6434