Statistical Power and Effect Size in Educational and Psychological Research Published in Journal of AL-MANARAH for Research and Studies

Abstract

This study aimes to assess to assess statistical power that was used in testing the null hypotheses and effect size in the educational and psychological research published in journal of AL-MANARAH for research and studies at Al al-Bayt University from 2010- 2014; and to detect the distribution of the used statistical power according to the different levels of the effect size. The current study included all the educational and psychological research that used (T- test & F- test) in all editions of this period. The number of these research articles was (87) and included (452) statistical tests, where (231) used the statistical (T- test) and (221) used the statistical (F- test). The necessary data was collected to achieve the study aims.Results of the study showed that about (26%) of the hypotheses contained a small effect size, and the average for (T- test) was (0.37), while the average for (F- test) was (0.13). Also, results revealed that around (63%) of the selected hypotheses had a weak statistical power test, around (11%) of the hypotheses had a medium statistical power test, and a round (26%) of the hypotheses had a large statistical power test. Finally, the study recommends that the researchers should provide the Editorial Board in AL-MANARAH journal with the amount of effect size and statistical power test besides statistical significance when they submit their research for publication in the journal.

Keywords: Effect Size, Statistical Significance, Statistical Power, Journal of AL-MANARAH for research and studies