Test Power, Effect Size and Sample Size of Published Research in Abhath Al-Yarmouk Hummanities and Social Science Series

Abstract

This study tried to evaluate the test power, effect size and
sample size of the research published in 16 volumes of Abhath Al-
Yarmouk- Hummanities and Social Sciences Series. The sample
consisted of 785 statistical test, where 3 conventional tests, were used,
namely the F test for ANOVA, the t test for means of independent
samples and the t test for the correlation coefficient. From data
reported by the studies, Cohen d as a measure of effect size was
calculated for each tested hypothesis and the power for the used
statistical test was obtained from tables prepared by Cohen.The study
concluded that the major factor behind the high percentage (72.5%)
of rejected hypotheses and the high percentage (52%) of statistical
tests reaching Cohen criterion for minimal power (0.8) might have
been the large sample size and not the effect size since hypotheses
associated with a large effect size were only 26.5%.