Tags: Colloquium Series

The Statistics Department hosts weekly colloquia on a variety of statistcal subjects, bringing in speakers from around the world.

This lecture is concerned with probability models for distance matrices, which are non-negative symmetric matrices of negative type. Several families of distributions are considered, including Wishart distance matrices and Mahalanobis distance matrices, all derived ultimately from Gaussian matrices by marginalization. The likelihood functions are obtained in a relatively straightforward manner without an explicit representation of the joint…
Commonly utilized in educational testing, models within the unidimensional item response theory (IRT) framework locate a student’s overall ability along a latent continuum by modeling the response probabilities to a set of test items as a function of a single continuous latent variable. Diagnostic classification models (DCMs) are an emerging class of models that, in contrast to IRT models, identify the separate components of what students know (…
Reliability or survival analysis is traditionally based on time-to-failure data. In high-reliability applications, there is usually a high degree of censoring, which causes difficulties in making reasonable inference. There are a number of alternatives to increasing the efficiency of reliability inference in such cases: accelerated testing, collection and use of extensive covariate information, and the use of multistate and degradation data when…
Last decade has seen rapid advances in genomic technologies. These technologies have provided researchers with tools to probe the genetic basis of complex diseases/traits. There is a wide gap between these genomic technologies and the developments of methods to analyze the massive data as well as lack of computer technologies to facilitate the analyses. The analysis and interpretation of the data they generate is exceptionally challenging due to…
Parametric and nonparametric models are convenient mathematical tools to describe characteristics of data with different degrees of simplification. When a model is to be selected from a number of parametric candidates, not surprisingly, differences occur when the data generating process is assumed to be parametric or nonparametric. In this talk, in a regression context, we will consider the question if and how we can distinguish between…
The availability of powerful computing equipment has had a dramatic impact on statistical methods and thinking, changing forever the way data are analysed. New data types, larger quantities of data, and new classes of research problem are all motivating new statistical methods. We shall give examples of each of these issues, and discuss the current and future directions of frontier problems in statistics.
We will provide a comprehensive review of basics of statistical meta-analysis and discuss its relevance for the problem of drawing inference about a common mean of several univariate normal populations with unknown and unequal variances. This problem, which is related to Behrens-Fisher problem, has many applications, and we will study two real data sets.
Exploring genomic landscapes of different biological endpoints is an important approach for understanding biological processes and disease etiologies. Examples of these endpoints are sequence composition, DNA methylation, histone modifications, and binding sites for different transcription factors. With the completion of human genome project and advances of high-throughput technologies, tightly spaced measurements have been collected from linear…
In mammalian cells, isoforms of a gene can have highly similar sequences yet encode proteins with remarkably different functional roles. Quantifying cellular abundance of isoforms is therefore of significant biological interest. In this talk, we will review methods for profiling isoform-specific gene expression using high-throughput technologies such as microarrays and ultra high-throughput RNA sequencing (RNA-Seq). We will show the intrinsic…
In this talk, I will present some new contributions to the area of high dimensional statistical learning. The focus will be on both classification and clustering. Classification is one of the central research topics in the field of statistical learning. For binary classification, we propose the Bi-Directional Discrimination (BDD) method which generalizes linear classifiers from one hyperplane to two or more hyperplanes. BDD provides a compromise…