1. (*) marked studies involved in the meta-analysis.
*Ablin-Stone, K. (2008). The effect of two dıfferent approaches to teachıng lıfe scıence on student achıevement (PhD Thesis). Idaho State University, Major in Education in the College of Graduate Studies, Moscow.
2. *Acar, E. N. (2011). The effect of project-based learning on pre-service science teachers' scientific process skills and attitudes towards biology. Master Thesis, Onsekiz Mart University, Çanakkale.
3. Acat, M. B. ve Dönmez, İ. (2009). To compare student centred education and teacher centred education in primary science and technology lesson in terms of learning environments. Procedia - Social and Behavioral Sciences, 1(1),1805-1809.
4. *Akçay, H., & Baltacı, A. (2017). Evaluation of multiple writing activities for learning in astronomy teaching. Mersin University Journal of Education Faculty, 13(1), 138-151.
5. Akgöz, S., Ercan, İ. ve Kan, İ. (2004). Meta-analysis. Journal of Uludag University Faculty of Medicine, 30(2), 107-112.