ABSTRACT EFFECTIVENESS OF CONCEPTUAL CHANGE INSTRUCTION ON OVERCOMING STUDENTS&#039 / MISCONCEPTIONS OF ELECTRIC FIELD, ELECTRIC POTENTIAL AND ELECTRIC POTENTIAL ENERGY AT TENTH GRADE LEVEL VATANSEVER, Orhan MS, Department of Secondary Science and Mathematics Education Supervisor: Dr. Mehmet Sancar December 2006, 107 pages The purpose of this study was to investigate the effectiveness of the conceptual change text based instruction over traditionally designed physics instruction to overcome tenth grade students&amp / #8217 / misconceptions on electric field, electric potential and electric potential energy concepts. To provide conceptual change, conceptual change texts (CCT) were developed by the researcher. An Electric Potential and Electric Potential Energy Concept Test (EPEPECT) which consists of 10-items was developed and used to examine students&amp / #8217 / probable misconceptions. Physics Attitude Scale (PATS) was administered to the students to obtain valid information concerning how conceptual change text based instruction effect students&amp / #8217 / attitudes toward physics. The subjects of this study included two tenth grade level classes from TED Ankara College Private High School in Ankara, Turkey, and a total of 37 students&amp / #8217 / scores were used for the statistical analysis. Students from one of the classes that were randomly assigned participated in traditional instruction and referred as the control group. Students from the other class participated in CCT based instruction and referred as the experimental group. EPEPECT and PATS had been administrated to both groups on two different occasions as pretest and posttest. According to the results of the study, statistically significant differences were found between conceptual change instruction and traditional method. Students taught with CCI showed a better scientific conception related to electric field, electric potential and electric potential energy and elimination of misconceptions than the students taught with traditionally designed physics instruction (TDPI). However, CCI did not increase the students&amp / #8217 / attitudes toward physics as school subject more than TDPI did. That is, conceptual change instruction was not effective in improving positive attitudes toward physics.

ABSTRACT SHEAR STRENGTH BEHAVIOUR OF SAND - CLAY MIXTURES &Ouml / LMEZ, Mehmet Salih M.S., Department of Civil Engineering Supervisor: Prof. Dr. Mehmet Ufuk ERGUN May 2008, 106 pages A clean sand having about 5 % fines has been mixed with 5 to 40 % commercial kaolin to form different sand-clay soil mixtures. The purpose of making this study is to observe the effects of fraction of fine materials in the soil mixture on the behavior of shear strength. Three series of experiments have been performed throughout the study. Undrained triaxial compression tests (series 1) are performed on specimens taken out from homogeneously mixed soil mixtures at specified kaolin contents consolidated in a box without keeping the mixture under water. In series 2 experiments specimens are taken from a box where soil mixtures are consolidated under water and undrained triaxial compression tests are performed on the samples. Drained direct shear tests are performed on samples prepared without performing initial consolidation in large boxes but directly prepared in the direct shear boxes and consolidated prior to shear (series 3). It has been found that about 20 % kaolin - 80 % sand mixture seems to be a threshold composition and changes in both undrained and drained shear stress-strength behaviour occur afterwards with increasing fine material content.

The purpose of this study is to investigate the effect of web supported statistics education environment for graduate level students. The aim was to develop a web support system to ease the graduate students&#039 / understanding of statistical concepts. This study also examined the perceptions of the students about web supported instruction. Although there are some studies conducted about technology aided statistics education, they are insufficient in the amount according to other areas. Besides these few studies were conducted mainly among lower grades. There is a need to find out and overcome students&rsquo / learning difficulties about statistical concepts in graduate levels. The intention of the study was to construct a web support system for traditionally offered Educational Statistics course in order to decrease both instructor and students efforts to communicate, present, reach and use the resources. The subjects of the study were 21 graduate students of Educational Statistics course offered. None of the subjects was offered an on-line course before. The study used both quantitative and qualitative measurements to analyze the effectiveness of the site and perceptions of the users. The results of the study indicated that there was an improvement in students&rsquo / achievement related to educational statistics through web supported instruction. Besides, the perceptions of the students were collected with interview questions about the functions and usability of the system. The highly positive perceptions of the students showed that, it is necessary for the students to have such a course support system. The framework was developed not only support for traditionally offered courses, but also support for lifelong learning processes. The researcher believed that the study revealed the most realistic usage pattern of a course support system. The results can be used by the instructors in order to offer the best web support system with minimum effort. Moreover, the proposed system can be used in any learning content management systems without the need for technical knowledge.

The purpose of study is to investigate the effects of school characteristics on students&rsquo / mathematics achievement across Turkey by analyzing the data collected from school questionnaire, student background questionnaire and mathematics achievement test in Trends in International Mathematics and Science Study 2007. The analyzed sample was comprised of 4,498 students in 146 schools. Student level factors were highest level of education of either parent, students speak the language of test at home, students&rsquo / parents born in country, books in home, computer and internet connection, computer use, index of time students spend doing mathematics homework in a normal school week, index of students&rsquo / positive affect toward mathematics, index of students&rsquo / valuing mathematics, index of students&rsquo / self confidence in learning mathematics. School related factors were principals reports on the percentages of students in their schools coming from economically disadvantaged homes, principals report on the percentage of students having the language of test as their native language, index of good attendance, principals time spent on various school related activities, schools encouragement of parental involvement, index of school resources for mathematics instruction, index of principals perception of school climate. Hierarchical Linear Modeling (HLM) was used for analysis. The result of the study showed that 45% of variance between schools, 54.6 % of variance was in schools, 57.33 % of school variance in mathematics achievement accounted by principals&rsquo / report on percentages of students coming from economically disadvantaged homes, parents to volunteer for school programs, school resources for mathematics instruction and principals&rsquo / perception of school climate.

In developing countries, there is a great demand for university education. In order to select students to universities a standardized test score is used. In Turkey, the Student Selection Test (SST) have important role in admission to universities. However, there is very limited knowledge about what SST mathematics sections actually measures. The main purpose of the present study is to evaluate the content of the mathematics subtest of the SST in line with mathematical cognitive skills and eventually provide construct related evidence for dimensionality of the test items. Within this framework, it is aimed to cross validate the mathematics subtest across gender groups, school types and two consecutive years. Also relations among mathematical abilities are investigated. This study is first in investigating what is measured by SST Mathematics sections and analyzing construct validity by testing several nested confirmatory factor models. Comparison of fit indices of five competitive models showed three-factor model has better fit indices in which Basic Computation Ability, Advanced Computation Ability and Geometry Ability is measured. It is concluded that problem solving items are not measuring a different process, but measures some sort of computation ability. There is a problem related to the content of the mathematics subtests of the SST in line with mathematical cognitive skills. Higher order cognitive skills are not measured properly. Three-factor model is tested about the invariance of the factors across gender, school types and years. It is concluded that invariant factor structure indicates that SST mathematics section is operating similarly for subgroups and years. The relations among mathematical abilities on three-factor model are investigated by item mapping and structural equation models. It is seen that Basic Computation Ability is a prerequisite to acquire Geometry Ability and Advanced Computation Ability.

The main aim of this thesis study is to identify the factors that affect higher education students&rsquo / perceptions of computerized assessment for learning. This study additionally aims to help effective use of computers in assessment activities by guiding the teachers or educational organization by interpreting the factors that affect students&rsquo / attitudes toward computer use in examinations. Quantitative research design has been used in this study. When choosing the participants, nonprobability sampling strategy was used due to its convenience. A total number 332 student of Middle East Technical University participated in the study. The data has been analyzed via Confirmatory Factor Analysis and interpreted by Structural Equation Modeling. The data loaded under 5 constructs: Perceived Ease of Use, Perceived Usefulness, Intention, Computer Attitude and Anxiety. By identifying the relations between these constructs, a structural model was created to determine the intention of students&rsquo / towards computerized assessment. The findings of this study have revealed that &ldquo / perceived usefulness&rdquo / is the most important determinant in students&rsquo / willingness to use computerized assessment. Additionally, if students have anxiety resulted from computer use, this affect their easiness perceptions negatively. Computer attitude is another factor that affects students&rsquo / perceptions of easiness and their anxiety. Finally it is concluded that students&rsquo / computer attitudes and anxiety affect their behaviors toward computerized assessment.

Until the developments in computer technology, linear test administrations within classical test theory framework is mostly used in testing practices. These tests contain a set of predefined items in a large range of difficulty values for collecting information from students at various ability levels. However, placing very easy and very difficult items in the same test not only cause wasting time and effort but also introduces possible extraneous variables into the measurement process such as possibility of guessing, chance of careless errors induced by boredom or frustration. Instead of administering a linear test there is another option that adapts the difficulty of test according to the ability level of examinees which is named as computerized adaptive test. Computerized adaptive tests use item response theory as a measurement framework and have algorithms responsible for item selection, ability estimation, starting rule and test termination. The present study aims to determine the applicability of computerized adaptive testing (CAT) to Turkish Pupil Monitoring System&rsquo / s (PMS) mathematics assessments. Therefore, live CAT study using only multiple choice items is designed to investigate whether to obtain comparable ability estimations. Afterwards, a Monte Carlo simulation study and a Post-hoc simulation study are designed to determine the optimum CAT algorithm for Turkish PMS mathematics assessments. In the simulation studies, both multiple-choice and open-ended items are used and different scenarios are tested regarding various starting rules, termination criterion, ability estimation methods and existence of exposure/content controls. The results of the study indicate that using Weighted Maximum Likelihood (WML) ability estimation method, easy initial item difficulty as starting rule and a fixed test reliability termination criterion (0.30 standard error as termination rule) gives the optimum CAT algorithm for Turkish PMS mathematics assessment. Additionally, item exposure and content control strategies have a positive impact on providing comparable ability estimations.

This study investigated the construct of comprehensible English in the context of oral proficiency assessment for international teaching assistants. I carried out a three-part mixed method design to explore instructor rater judgments, results of a speech analysis, and how specific speech variables might have influenced judgments on the assessment criteria. Each step focused on a failed/passed assessment comparison made possible through archived data from which 10 individuals initially failed the oral proficiency test but within the same year retook the task and received a passing score. Part A evaluated the perspective of the instructor raters through the rating scale judgments provided on the assessment evaluation forms. In the second part of the study, I coded and scored grammatical, temporal, and phonological variables that occurred on two-minute excerpts of a field-specific summary task from the set of 10 failed and then subsequently passed assessments performed by the same individuals. I inspected the speech analysis results to evaluate differences in the values of specific speech variables on the set of failed performances in comparison to the set of passed performances. In Part C, I conducted 10 case studies to compare each individual's rating scale judgments and rater comments on grammar, fluency, and pronunciation from their failed and their passed assessment with the results from the speech analysis of grammatical, temporal, and phonological variables. The case study approach facilitated a broad inspection of the interrelation among the rater perspectives on the assessment criteria and the speech analysis results. The study findings showed evidence of an interrelation between temporal and phonological variables on rater judgments of comprehensibility, as well as the role of pronunciation as a criterion for oral proficiency assessments. I concluded with implications for future research on the interrelation among speech variables that influence listener perceptions of comprehensibility and the use of pronunciation as a speaking assessment criterion. / text

published_or_final_version / Public Administration / Master / Master of Social Sciences

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