A lofistic rlgression analysis of response-time data where the hazard function is time dependent

A logistic-exponential model for analyzing response-time data involving regressor variables is modified to allow for non-consrarey of the hazard function. For the discrete observation case illustrated the logit of the probability of responding in a time interval cf arbitrary length is taken as the sum of a function of resressor variables and a function of the time variable. The particular functions chosen in the two medical examples analyzed are linear in the parameters involved. A polynomial function of time is employed in the absence of knowledge as to a more appropriate form. Various issues arising in the analysis made are discussed.     

Exclusion restrictions in instrumental variables equations

In this paper we consider two-stage estimators of parameters of a structural equation in a model with recursive exclusion restrictions on the instrumental variables equations. The estimations considered are simple OLS and GLS estimators after substitution of estimates of the systematic part of the IV equations for the endogenous variables. It is known in the literature that neither imposing the restrictions in the first stage nor ignoring them will in general be more efficient than the alternative. We introduce a class of mixed instrumental variables estimators (MIV) with these possibilities as special cases which yields an estimator which is not only more efficient than the two stage estimators considered in the literature but as efficient as an efficient system estimator like 3SLS.     

Analysis of a factorial quantal response assay using inverse regression

An inverse regression approach to analyzing quantal response assays with one quanritative independent- variable and any number of qualitative independent variables is presented. A general factorial model ror LQC- inverted relationship and methods of testing hypotheses estimating qulitative Interest are developed. This naper provides a modified method of analysis which is easier to apply than previously existing methods.     

On a nonparametric test for the mixed-model

Nonparametric tests for the null hypothesis of no treatment effect in the mixed-model experiment which involves n randomly chosen subjects who respond once to each of ρ distinct treatments have been developed by Koch and Sen (1968), These tests were based on the assumption of compound symmetry of the error vectors and on the weaker assumption of diagonal symmetry of the error vectors. This paper considers an alternative (permutationally) distribution-free test under this latter assumption. The new test follows the same type of distribution theory as those in Koch and Sen, but utilizes the inherent invariance structure in a more visable and direct way.     

Unobserved-Components Models for Seasonal Adjustment Filters

Time series models are presented, for which the seasonal-component estimates delivered by linear least squares signal extraction closely approximate those of the standard option of the widely-used Census X-11 program. Earlier work is extended by consideration of a broader class of models and by examination of asymmetric filters, in addition to the symmetric filter implicit in the adjustment of historical data. Various criteria that guide the specification of unobserved- components models are discussed, and a new preferred model is presented. Some nonstandard options in X-11 are considered in the Appendix.     

Tests for Cointegration Breakdown Over a Short Time Period

We derive a speculative trading model with endogenous informed trading that yields a conditionally heteroscedastic time series for trading volume and the squared price changes. We use half-hourly price-change and volume data for IBM during 1988 to test the model and estimate the structural parameters using the simulated method-of-moments estimation procedure. Although the model seems to do a reasonable job fitting the unconditional moments of the volume and the squared price change processes, it fares less well in fitting the relation between current trading volume and lags of trading volume and squared volume's (and its lag's) relation to squared price changes.     

The implementation of the bayesian paradigm

Routine implementation of the Bayesian paradigm requires an efficient approach to the calculation and display of posterior or predictive distributions for given likelihood and prior specifi- cations. In this paper we shall review some of the analytic and numerical approaches currently available, describing in detail a numerical integration strategy based on Gaussian quadrature, and an associated strategy for the reconstruction and display of distributions based on spline techniques.     

Adolescent Socialization in Rural Appalachia: The Perspectives of Teens,Parents, and Significant Adults

ABSTRACT

The purpose of this qualitative study was to explore the social networks of Appalachian adolescents to understand socialization strategies and goals. A total of 46 interviews were conducted with five families (mothers, fathers, and adolescents) and 11 socialization agents the families identified as exerting significant influence in the lives of the adolescents. Interviews were transcribed and then analyzed using principles of grounded theory. Five themes developed from the interviews: the importance of community to the socialization process, adult involvement and support, adolescent monitoring, teaching respect and responsibility, and adolescent autonomy. Results suggest the need for in-depth investigation of adolescent development within a variety of cultural and social contexts to more fully understand these processes.