Bootstrap methodology is presented that yields approximations of the sampling variation of redundancy estimates while assuming little a priori knowledge about the distributions of these statistics. Results of numerical demonstrations suggest that bootstrap confidence intervals may offer substantial assistance in interpreting the results of…

Monte Carlo methods are used to explore the accuracy of a method for establishing confidence intervals for variance component estimates in generalizability studies. Previous research has shown that variance component estimation errors due to sampling are often larger than suspected. (Author/CM)

The wide availability of large amounts of inexpensive computing power has encouraged statisticians to explore many approaches to a basis for inference. This paper presents one such "computer-intensive" approach: the bootstrap of Bradley Efron. This methodology fits between the cases where it is assumed that the form of the distribution…

BRRVAR, which uses the Balanced Repeated Replication approach, was designed for use with the Statistical Analysis System (SAS). It was created for the National Center for Education Statistics, to enlarge their capacity to estimate and analyze sampling errors for statistics generated from educational surveys with complex sampling designs. BRRVAR…

A normally distributed data set of 1,000 values--ranging from 50 to 150, with a mean of 50 and a standard deviation of 20--was created in order to evaluate the bootstrap method of repeated random sampling. Nine bootstrap samples of N=10 and nine more bootstrap samples of N=25 were randomly selected. One thousand random samples were selected from…

The effects of certain characteristics (e.g., sample design) of National Assessment of Educational Progress (NAEP) data on statistical analysis techniques are considered. Ignoring special features of NAEP data and proceeding with a standard analysis can produce inferences that underestimate the true variability and overestimate the true degrees of…

The Schools and Staffing Survey (SASS) is an integrated system of surveys of public and private schools, school districts, school administrators, and teachers conducted by the National Center for Education Statistics (NCES). This collection contains papers related to the SASS presented at meetings of the American Statistical Association in August…

Empirical comparisons are made of three statistical sampling methods evaluated for estimating total number of relevant documents in collection for given query: simple random sampling, random sampling which assigns unequal selection probabilities to individual documents in collection, and curve fitting and extrapolation. Nine references and…

Tracking and two statistical methods (probability weighting and sample selection modeling) were studied as ways to minimize bias attributable to sample attrition in school-based studies. Data on student smoking from 30 middle schools illustrate that sample weighting yields the best results, with estimates superior to sample selection and much less…

Describes advances in capture-recapture modeling, including the biologically motivated emphasis on model-based hypothesis testing and the development of models for spatially stratified populations. Discusses the severe problems associated with count statistics reflecting unknown sampling fractions. (67 references) (KR)

Normative data for the Wechsler Memory Scale-Revised were derived empirically using a sample of 50 volunteers between 25 and 34 years of age, who matched U.S. Census data on demographic characteristics. Differences between these empirical norms and published norms that were estimated statistically appear clinically significant. (SLD)

The Integrated Postsecondary Education Data System (IPEDS) of the National Center for Education Statistics collects data from all sections of postsecondary education. For less-than-two-year institutions, the IPEDS collects data on fall enrollment, completions (earned awards and certificates), etc., from all public institutions in that category and…

Effect sizes have been increasingly emphasized in research as more researchers have recognized that: (1) all parametric analyses (t-tests, analyses of variance, etc.) are correlational; (2) effect sizes have played an important role in meta-analytic work; and (3) statistical significance testing is limited in its capacity to inform scientific…

In studies involving matrix sampling on items, it is often the case that there are too few responses per individual to use latent trait item response models. A model is formulated wherein individual level variability appears as independent error within the cells of a cross classification of demographic variables. (JKS)

The Schools and Staffing Survey (SASS) of the National Center for Education Statistics provides periodic, timely data on public and private elementary and secondary schools in the United States. Data collected include: school and teacher characteristics; school operations, programs, and policies; teacher demand and supply; and the opinions of…