حجم تأثير الإختبارات الإحصائية المعلمية واللامعلمية المستخدمة في رسائل الماجستير بكلية التربية بجامعة الملك سعود
The present study aimed at identifying important statistical procedures used for calculating effect size of parametric and nonparametric tests in master theses registered at Faculty of Education-King Saud University from 1995 to 2008. Moreover, it explored the current usage of effect size and whether this varies according to the methods used (i.e., descriptive, or experimental) or the sample sizes (i.e., small, medium, or large. The researcher tried to answer the following questions: 1) what are the parametric and nonparametric tests used in master theses registered at Faculty of Education King Saud University? 2) What is the current usage of effect size in parametric and nonparametric tests used in master theses registered at Faculty of Education King Saud University? 3) What are the effect sizes used in parametric and nonparametric tests used in master theses registered at Faculty of Education King Saud University? The study results were as follows: 1) the most statistical procedures used at Faculty of Education-King Saud University were parametric tests (frequency=559, 93.48 %), and the t-test was the most common among them (frequency=256,42.81%). 2) Effect size was rarely used at Faculty of Education-King Saud University (frequency=2,1.3%). 3) Effect size for the statistical procedures used at Faculty of Education King Saud University ranged from small to medium. The researcher concluded with the following recommendations: 1) teaching nonparametric tests and integrating them into courses for postgraduate students. 2) Encouraging researchers to calculate effect sizes for the statistical procedures used for testing their hypotheses. 3) Integrating effect size into courses for post graduate students. 4) In addition to the traditional use of statistical significance, the researcher encourages the inclusion of effect size in the results of published studies. (Published abstract)