Investigating the Effect of Missing Data on the Experimental Test of Mathematics for the Second-Secondary Students

This study aimed to uncover the effect of the missing values using the Rasch model on an experimental test of mathematics for the second-secondary students. To achieve the goal of the study, a multiple-choice test was designed testing all basic skills found on the student’s book. The test consisted of 103 items. This study was conducted in September 2019. The results were analyzed using SPSS, Winstep, and MG3-BILOG. To determine the correlation coefficients, the results showed that the test had good psychometric properties and the test had high reliability, validity indications, acceptable difficulty, and discrimination coefficients. The findings also showed that the differentiation coefficients of items were equal. The results also showed that the premises of the Rasch model were fulfilled. Further, the results showed that there were statistically significant differences between the three models according to the percentage of data loss, standard error, difficulty, internal and external matching, and bias, and were in favor of the original model before missing the values

Self-Concept and Its Relationship with Academic Procrastination Among the Secondary Stage Students at Ajloun Governorate "Evaluation Study"

The study aimed to reveal the level of prevalence of the academic procrastination phenomenon among the secondary stage students at Ajloun Governorate center, and to reveal the differences between the male and female students from the scientific and literary streams, in addition to identifying the relationship between the self-concept and academic procrastination among the study sample, and the extent to which the self- concept explains the variance in the academic procrastination behavior. The population of the study consisted of (3445) male and female secondary stage students at Ajloun Directorate of Education, the study sample was (344) male and female students. To achieve the objectives of the study, the researchers used two scales: self- concept scale developed by El-Ghamdi (2009), and academic procrastination scale developed by Tamimi (2012) after checking their reliability and validity. The results of the study showed that there is prevalence of academic procrastination and to a medium degree, and the level of self-concept in the research sample was medium. In addition to the absence of statistical significance differences in the degree of academic procrastination due to gender variable. As well as the existence of statistical significant differences in the degree of academic procrastination due to the specialization variable and the differences were in favor of (scientific specialization) with a mean of (2.18). Finally, the results showed a statistically significant relationship between self-concept and academic procrastination. Keywords: Academic procrastination, Self- concept, Secondary Stag