Efforts to understand growth and disparities in science achievement have mainly been focused on the middle and high school grades in studies of K – 12 science education, leaving a gap in the research about the early elementary years. This study used a nationally-representative sample of students in Grades K – 2 to examine science achievement and growth trajectories of students by gender and race/ethnicity. Using multilevel growth modeling, differences in science achievement at Grade 2 and in rate of growth were detected for several student groups. Socioeconomic status, prior reading and math achievement, and student home language status were also significant predictors of science achievement. Growth effect size estimates were calculated by student group and showed substantial year-to-year growth in science achievement in the early elementary grades, with a slight decrease in effect size across years. In order to strengthen current efforts to increase student engagement and participation in science and STEM-related career and college pathways, especially for historically underrepresented groups, policymakers should shift focus to better understand promising practices that best support all students in science from the onset of their K – 12 educational experience.

The purpose of this study employing meta-analysis was to assess the impact that after-school programs have on reading and mathematics outcomes. The participants in the primary studies were students in Grades K through 8; years 200 through 2009. The study utilized the theory of change as its theoretical basis. This meta-analysis used the effect size as the standard measure. It began with an overall Cohen's d of .40 for the impact that after-school programs have on reading and mathematics outcomes, and then proceeded to analyze three moderator variables: subject, time periods, and grade level.The findings of the meta-analysis, both overall and sub analyses, show that the independent variable, after-school programs, has an impact on the dependent variable, reading and mathematics. The overall results indicated that after-school programs are educationally significant in the areas of reading and mathematics combined. As for the moderator variable, the results for the areas of (a) subject (reading and mathematics), (b) time period (2000-2002, 2003-2005 and 2006-2009), and (c) grade (middle, and middle plus elementary combined), all indicated educationally significant results. The notable exception was the grade moderator, elementary.This study provides more information for researchers, practitioners and policy makers upon which to make practical research based decisions about after-school programs for the purpose of determining the applicability of such in their educational setting.

Although, it is well established that regular exercise has a positive effect on various domains of cognitive functions, effects of a single session (acute) exercise on cognitive functions of an young adult is under debate. While a numbers of research have found positive associations between acute exercise and cognitive performance, multiple research have found no effect of acute exercise on the cognitive functions. There are also evidences that suggest that acute exercise reduces brain function of healthy young adults. This thesis took on a meta-analytical approach to determine the effect of a single session exercise on the cognitive functions of healthy young adults, and metaregression analyses were performed to identify the moderators that may influence the effect of acute exercise on cognitive functions of healthy young adults. After a comprehensive electronic search 59 experimental studies were found to be eligible for inclusions based on the pre-specified criteria. Results indicated that acute exercise has a small but significant effect on the cognitive functions of healthy young adults. However, larger effects are possible for particular cognitive outcomes (reaction time), when specific exercise parameters are used (5 minutes of exercise duration, moderate intensity exercise), and when specific assessment task is used (visual span board task, and serial subtraction of 7). The overall findings of this study is consistent with previous research. However, more research is needed to get a clear understanding of the acute exercise effect moderators.

The focus of this study was to conduct a meta-analytic investigation to combine the results obtained in independent studies aimed at determining the effectiveness of using digital games, as opposed to traditional methods, as a strategy for improving students' performance in high school mathematics. The major question of this study is: "Does the research on the use of games in high school mathematics support the use of games as a teaching strategy for improving student achievement?" To answer this question, meta-analysis was employed. Meta-analysis synthesizes and analyzes the quantitative data collected in independent and multiple empirical studies carried out on similar topics, situations, and hypotheses in order to reach a general judgment regarding the results of these studies. To determine which studies to use, specific criteria including articles published in refereed journals, thesis, and dissertation studies with experimental and control groups, research with effect size, sample size, standard deviation, and means. Based on these criteria, it was decided to include six experimental studies in the meta-analysis. The result showed that there was no significant differences between the use of digital games and traditional methods to teach mathematics in high school. The weighting factor of the two variables, standard deviation and number of participants, may account for the lack of support for gaming over traditional method of instruction.

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In studies where the response variable is measured on a ratio scale, a ratio of means or medians provides a standardized measure of effect size that is an alternative to the popular standardized mean difference. Confidence intervals for ratios of population means and medians in independent-samples designs and paired-samples designs are proposed as supplements to the independent-samples t test and paired-samples t test. The performance of the proposed confidence intervals are evaluated in a simulation study. The proposed confidence interval methods are extended to the case of a 2 × m factorial design that includes propensity score stratification and meta-analysis as special cases. R functions that implement the recommended confidence intervals are provided in the Supplemental Material file, available in the online version of this article, and are illustrated with several examples.

The Association of Research Libraries (ARL) provides an option for librarians to administer a combination of LibQUAL+® and LibQUAL+® Lite to measure users' perceptions of library service quality. LibQUAL+® Lite is a shorter version of LibQUAL+® that uses planned missing data in its design. The present study investigates the loss of information in commonly administered proportions of LibQUAL+® and LibQUAL+® Lite when compared to administering LibQUAL+® alone. Data from previous administrations of LibQUAL+® protocol (2005, N = 525; 2007, N = 3,261; and 2009, N = 2,103) were used to create simulated datasets representing various proportions of LibQUAL+® versus LibQUAL+® Lite administration (0.2:0.8, 0.4:0.6. 0.5:0.5, 0.6:0.4, and 0.8:0.2). Statistics (i.e., means, adequacy and superiority gaps, standard deviations, Pearson product-moment correlation coefficients, and polychoric correlation coefficients) from simulated and real data were compared. Confidence intervals captured the original values. Root mean square errors and absolute and relative biases of correlations showed that accuracy in the estimates decreased with increase in percentage of planned missing data. The recommendation is to avoid using combinations with more than 20% planned missing data.

no / Medical statistics is a vast and ever-growing field of academic endeavour, with direct application to developing the robustness of the evidence base in all areas of medicine. Although the complexity of available statistical techniques has continued to increase, fuelled by the rapid data processing capabilities of even desktop/laptop computers, medical practitioners can go a long way towards creating, critically evaluating and assimilating this evidence with an understanding of just a few key statistical concepts. While the concepts of statistics and ethics are not common bedfellows, it should be emphasised that a statistically flawed study is also an unethical study.[1] This review will outline some of these key concepts and explain how to interpret the output of some commonly used statistical analyses. Examples will be confined to two-group tests on independent samples, using both a continuous and a dichotomous/binary outcome measure.

This exploratory synthesis of research was the product of three years of dissertation research efforts that systematically reviewed 23 years of empirical articles between 1983 (or its inception) and 2006 from three of the most highly regarded educational administration journals. Specifically designed to collect investigative data and information from primary research contained within Educational Administration Quarterly, the Journal of School Leadership, and the Journal of Educational Administration; this research synthesis drew upon various research methods to propose pragmatic insights and proffer an empirically founded response to: What has the educational administration profession learned from the research efforts that were independently conducted, presented, and published about the overall connections between school superintendents and education's technical core -teaching and learning in schools? Results from employing meta-analysis, descriptive synthesis, and thematic synthesis techniques to appropriately collect and analyze relevant data indicate that school superintendents remain directly connected to the technical core; however, these connections have evolved from the traditional connections presently maintained by campus administrators and to new connections that meet the increased responsibilities and complexities of the superintendents' role. The thematic synthesis, reinforced by descriptive syntheses, indicated 15 separate superintendent - technical core constructs that promote new areas for investigation; however, the extent and strength of these constructs have yet to be determined. The impact from the next step suggestions for future research indicate that effects could range from educational administration knowledge base contributions to refining in-practice standards and professional development programs. The possible knowledge base contributions, coupled with specific in-practice elements that demonstrate superintendents' direct impact on the technical core, may be the necessary raw materials from which a foundational framework that clearly redefines the superintendent - technical core connections may be forged by scholars and implemented by district leaders to improve teaching and learning in schools.

A generalized design-comparable effect size modeling and estimation for multiple baseline designs across individuals has been proposed and evaluated by Restricted Maximum Likelihood method in a hierarchical linear model using R. This report evaluates the exact approach of the modeling and estimation by SAS. Three models (MB3, MB4 and MB5) with same fixed effects and different random effects are estimated by PROC MIXED procedure with REML method. The unadjusted size and adjusted effect size are then calculated by matrix operation package PROC IML. The estimations for the fixed effects of the three models are similar to each other and to that of R. The variance components estimated by the two software packages are fairly close for MB3 and MB4, but the results are different for MB5 which exhibits boundary conditions for variance-covariance matrix. This result suggests that the nlme library in R works differently than the PROC MIXEDREML method in SAS under extreme conditions. / text