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Pesterfield, Lester L.; Maddox, Jeremy B.; Crocker, Michael S.; Schweitzer, George K. – Journal of Chemical Education, 2012
"E"-pH (Pourbaix) diagrams provide an important graphical link between the thermodynamic calculations of potential, pH, equilibrium constant, concentration, and changes in Gibbs energy and the experimentally observed behavior of species in aqueous solutions. The utility of "E"-pH diagrams is extended with the introduction of an additional…
Descriptors: Inorganic Chemistry, Visual Aids, Computation, College Science
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Baeza-Baeza, Juan J.; Garcia-Alvarez-Coque, M. Celia – Journal of Chemical Education, 2012
A general systematic approach including ionic strength effects is proposed for the numerical calculation of concentrations of chemical species in multiequilibrium problems. This approach extends the versatility of the approach presented in a previous article and is applied using the Solver option of the Excel spreadsheet to solve real problems…
Descriptors: Chemistry, Computation, Computer Software, Spreadsheets
Goldhaber, Dan; Chaplin, Duncan – National Center for Analysis of Longitudinal Data in Education Research, 2012
In a provocative and influential paper, Jesse Rothstein (2010) finds that standard value-added models (VAMs) suggest implausible future teacher effects on past student achievement, a finding that obviously cannot be viewed as causal. This is the basis of a falsification test (the Rothstein falsification test) that appears to indicate bias in VAM…
Descriptors: Teacher Effectiveness, Academic Achievement, Models, Statistical Bias
Chung, Yeojin; Rabe-Hesketh, Sophia; Gelman, Andrew; Dorie, Vincent; Liu, Jinchen – Society for Research on Educational Effectiveness, 2012
Hierarchical or multilevel linear models are widely used for longitudinal or cross-sectional data on students nested in classes and schools, and are particularly important for estimating treatment effects in cluster-randomized trials, multi-site trials, and meta-analyses. The models can allow for variation in treatment effects, as well as…
Descriptors: Statistical Analysis, Models, Computation, Maximum Likelihood Statistics
Du, Jie – ProQuest LLC, 2012
While the question of how to use human knowledge to guide evolutionary search is long-recognized, much remains to be done to answer this question adequately. This dissertation aims to further answer this question by exploring the role of domain knowledge in evolutionary computation as applied to real-world, complex problems, such as financial…
Descriptors: Mathematics, Investment, Knowledge Level, Computation
Stevenson, Glenn A. – ProQuest LLC, 2012
For decades software managers have been using formal methodologies such as the Constructive Cost Model and Function Points to estimate the effort of software projects during the early stages of project development. While some research shows these methodologies to be effective, many software managers feel that they are overly complicated to use and…
Descriptors: Computer Software, Computation, Program Development, Administrators
Shadish, William R.; Rindskopf, David M.; Hedges, Larry V.; Sullivan, Kristynn J. – Online Submission, 2012
Researchers in the single-case design tradition have debated the size and importance of the observed autocorrelations in those designs. All of the past estimates of the autocorrelation in that literature have taken the observed autocorrelation estimates as the data to be used in the debate. However, estimates of the autocorrelation are subject to…
Descriptors: Bayesian Statistics, Research Design, Correlation, Computation
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Jiang, Yanlin; von Davier, Alina A.; Chen, Haiwen – Journal of Educational Measurement, 2012
This article presents a method for evaluating equating results. Within the kernel equating framework, the percent relative error (PRE) for chained equipercentile equating was computed under the nonequivalent groups with anchor test (NEAT) design. The method was applied to two data sets to obtain the PRE, which can be used to measure equating…
Descriptors: Equated Scores, Evaluation, Error of Measurement, Computation
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Albright, Brian – College Mathematics Journal, 2012
We describe the calculation of the distribution of the sum of signed ranks and develop an exact recursive algorithm for the distribution as well as an approximation of the distribution using the normal. The results have applications to the non-parametric Wilcoxon signed-rank test.
Descriptors: Computation, Tests, College Mathematics, Problem Solving
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Perruchet, Pierre; Poulin-Charronnat, Benedicte – Journal of Memory and Language, 2012
Endress and Mehler (2009) reported that when adult subjects are exposed to an unsegmented artificial language composed from trisyllabic words such as ABX, YBC, and AZC, they are unable to distinguish between these words and what they coined as the "phantom-word" ABC in a subsequent test. This suggests that statistical learning generates knowledge…
Descriptors: Artificial Languages, Probability, Models, Simulation
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Anastasio, Daniel; McCutcheon, Jeffrey – Chemical Engineering Education, 2012
A crossflow reverse osmosis (RO) system was built for a senior-level chemical engineering unit operations laboratory course. Intended to teach students mass transfer fundamentals related to membrane separations, students tested several commercial desalination membranes, measuring water flux and salt rejections at various pressures, flow rates, and…
Descriptors: Chemical Engineering, Scientific Concepts, Undergraduate Study, Science Laboratories
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de Leeuw, Christiaan; Klugkist, Irene – Multivariate Behavioral Research, 2012
In most research, linear regression analyses are performed without taking into account published results (i.e., reported summary statistics) of similar previous studies. Although the prior density in Bayesian linear regression could accommodate such prior knowledge, formal models for doing so are absent from the literature. The goal of this…
Descriptors: Data, Multiple Regression Analysis, Bayesian Statistics, Models
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Adams, Raymond J.; Wu, Margaret L.; Wilson, Mark – Educational and Psychological Measurement, 2012
The Rasch rating (or partial credit) model is a widely applied item response model that is used to model ordinal observed variables that are assumed to collectively reflect a common latent variable. In the application of the model there is considerable controversy surrounding the assessment of fit. This controversy is most notable when the set of…
Descriptors: Item Response Theory, Models, Computation, Classification
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Raykov, Tenko – Educational and Psychological Measurement, 2012
A latent variable modeling approach that permits estimation of propensity scores in observational studies containing fallible independent variables is outlined, with subsequent examination of treatment effect. When at least one covariate is measured with error, it is indicated that the conventional propensity score need not possess the desirable…
Descriptors: Computation, Probability, Error of Measurement, Observation
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Lei, Pui-Wa; Zhao, Yu – Applied Psychological Measurement, 2012
Vertical scaling is necessary to facilitate comparison of scores from test forms of different difficulty levels. It is widely used to enable the tracking of student growth in academic performance over time. Most previous studies on vertical scaling methods assume relatively long tests and large samples. Little is known about their performance when…
Descriptors: Scaling, Item Response Theory, Test Length, Sample Size
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