Browsing by Subject "Markov Chain Monte Carlo"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Effects of sample size, ability distribution, and the length of Markov Chain Monte Carlo burn-in chains on the estimation of item and testlet parameters(2011-05) Orr, Aline Pinto; Dodd, Barbara Glenzing; Suh, YoungsukItem Response Theory (IRT) models are the basis of modern educational measurement. In order to increase testing efficiency, modern tests make ample use of groups of questions associated with a single stimulus (testlets). This violates the IRT assumption of local independence. However, a set of measurement models, testlet response theory (TRT), has been developed to address such dependency issues. This study investigates the effects of varying sample sizes and Markov Chain Monte Carlo burn-in chain lengths on the accuracy of estimation of a TRT model’s item and testlet parameters. The following outcome measures are examined: Descriptive statistics, Pearson product-moment correlations between known and estimated parameters, and indices of measurement effectiveness for final parameter estimates.Item A review on computation methods for Bayesian state-space model with case studies(2010-05) Yang, Mengta, 1979-; McCulloch, Robert E. (Robert Edward); Sager, Thomas W.Sequential Monte Carlo (SMC) and Forward Filtering Backward Sampling (FFBS) are the two most often seen algorithms for Bayesian state space models analysis. Various results regarding the applicability has been either claimed or shown. It is said that SMC would excel under nonlinear, non-Gaussian situations, and less computationally expansive. On the other hand, it has been shown that with techniques such as Grid approximation (Hore et al. 2010), FFBS based methods would do no worse, though still can be computationally expansive, but provide more exact information. The purpose of this report to compare the two methods with simulated data sets, and further explore whether there exist some clear criteria that may be used to determine a priori which methods would suit the study better.