Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 147 for “"standard errors"”.
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A Comparative Simulation Study of Robust Estimators of Standard Errors
The estimation of standard errors is essential to statistical inference. Statistical variability is inherent within data, but is usually of secondary interest; still, some options exist to deal with this variability. One approach is to carefully model the covariance structure. Another approach is …
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Using Robust Standard Errors to Combine Multiple Regression Estimates with Meta-Analysis
… a small number of study samples did the robust standard errors noticeably lose efficiency. Combining sample-dependent focal slope estimates provides biased point estimates, however, the results of this paper suggest that the robust standard errors are still accurate.</p>
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Investigation of bootstrap estimates of the parameters, their standard errors, and associated confidence intervals of structural equation models with ordered categorical variables
… study focuses on the parameter estimates, their standard errors and the coverage rates of the associated bootstrap confidence intervals. Structural equation models are used widely in many disciplines and often the data analyzed involve ordered categorical variables. The performance of the …
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A Comparison of Kernel Equating and Traditional Equipercentile Equating Methods and the Parametric Bootstrap Methods for Estimating Standard Errors in Equipercentile Equating
… the parametric bootstrap method for estimating standard errors of equating. A two-parameter logistic item response theory (2-PL IRT) model was used to create population score distributions for different test sizes. Samples were drawn from the populations for different examinee sizes and the …
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Statistical modeling of longitudinal survey data with binary outcomes
… Taylor Linearization and bootstrap estimation of standard errors (design-based approach). The incidence of asthma (event history analysis) was estimated using weighted, unweighted and robust methods. Recurrent event history analysis was conducted using Anderson and Gill, Wei, Lin and Weissfeld …
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Longitudinal analysis for binary and count data
… estimates of regression parameters and their standard errors. Unfortunately, the correlation structure in the data for each subject may not be well understood, making such parametric modelling difficult. This thesis discusses two methods for the analysis of longitudinal data which require only …
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Estimating Site Productivity from Non-Site Trees: A Site Index Based Approach
… models performed the best. These models had standard errors ranging from 5.0’ to 7.8’ and explained about 80% of the variation in observed SI with no bias. For comparison’s sake, soil/site models (no tree attributes used in prediction) typically have standard errors in the 6.25’ to 9.0’ …
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Estimating Site Productivity from Non-Site Trees: A Site Index Based Approach
… models performed the best. These models had standard errors ranging from 5.0’ to 7.8’ and explained about 80% of the variation in observed SI with no bias. For comparison’s sake, soil/site models (no tree attributes used in prediction) typically have standard errors in the 6.25’ to 9.0’ …
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The Relation between Uncertainty in Latent Class Membership and Outcomes in a Latent Class Signal Detection Model
… of one of being in the assigned class. Finally, standard errors are underestimated because the residual uncertainty about the latent class membership is ignored. This dissertation used simulation studies and an analysis of a real-world data set to compare five commonly adopted approaches (most …
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The place of crossover designs in infertility trials
… allowing women to get pregnant twice has lower standard errors than treatment estimates obtained by conducting the realistic infertility trials. In the scenario involving no period effects the two treatment estimates are not biased. In the scenario involving period effect, the standard errors of …
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The robustness of LISREL estimates in structural equation models with categorical data
… and unweighted least squares estimates. The standard errors of the estimates were found to be inflated, making significance tests unreliable. The analysis of mixed matrices produced average estimates that more closely approximated the model parameters except in the case where the dichotomous …
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Near-Infrared Analysis and Process Control of Pharmaceutical Pelletization Processes
… were effectively accomplished with average standard errors of prediction of 1.11% and 0.63%, respectively. Near-IR prediction of pellet potency of pilot-scale batches was also achieved using data from laboratory-scale experiments. For Wurster coating operations, in-line and at-line near-IR …
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Use of ultrasound technology in the genetic improvement of U.S. lamb composition
… for LEA, BF, and BW, respectively; prediction standard errors ranged from 1.86 to 2.22 cm2, 0.12 to 0.14 cm, and 0.35 to 0.38 cm, respectively. Repeatability standard errors ranged from 1.61 to 2.45 cm2, 0.07 to 0.11 cm, and 0.36 to 0.42 cm for LEA, BF, and BW, respectively. Changes in …
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Development of Dispersive and Fourier Transform Near Infrared Spectroscopy Methodology for Food and Edible Seed Analysis
… These calibrations are characterized by low standard errors (<∼1.0% for protein, fat and moisture) and also by high degrees of correlation (∼99%). The first calibrations for soybean isoflavones reported here were also characterized by low standard errors (<0.02%) and high degrees of …
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On Logistic Regression Approach to Survival Data and Power Divergence Statistics for Life Tables
Efron (1988) proposes the use of standard logistic regression techniques to estimate hazard rates and survival curves from survival data. These techniques allow statisticians to use parametric regression modeling on survival data in a flexible way that provides both estimates and standard errors. …
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An examination of the price reaction to the announcement of bond issues by Johannesburg Stock Exchange listed companies on the Bond Exchange of South Africa
… returns. The average abnormal returns are standardised by their time series standard errors of regression and tested for significance by the t-test. The evidence indicates that the null hypothesis should not be rejected. Furthermore, the study is examined within the context of contemporary …
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Who Benefits? The Effects of Foreign Aid and Foreign Direct Investment on Human Rights
… squares regression analyses with panel-corrected standard errors on a pooled cross-sectional time series design incorporating 127 countries from 1976 to 1996. While my results are not significant, it is important to observe that there is a tendency toward negative relationships for the majority of …
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A longitudinal behavior genetic model for ordered categorical variables
… in all conditions although estimates of standard errors were biased and statistical powers to detect non-zero parameters were not sufficient for some parameters. A potential solution for these irregularities was discussed. Despite these limitations, the relative contributions of genetic …
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Impacts of Ignoring Nested Data Structure in Rasch/IRT Model and Comparison of Different Estimation Methods
… observation, however, is ignored in the current standard practices which apply the standard Rasch/IRT for the large scale testing data. A simulation study (Study Two) was conducted to address this issue of the effects of ignoring nested data structure in Rasch/IRT models under various conditions, …
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Evaluation of the Effect of the Clinical-Decision-Support Systems on Diabetes Management: A Multivariate Meta-Analysis Comparison with Univariate Meta-Analysis
… equally when no missing data were present. The standard errors of the estimates in both methods were reduced by increasing the sample size with more reduction in standard errors found in MVMA. The results of UVMA and MVMAs of CDSSs’ effect concluded that CDSSs had a significant effect on …
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