Perfect cells,direct models and contingency table outliers

A peifect cell frequency is one exactly satisfying a given model General formulae foi peifect cells are provided for direct models having two Or hiee components. Foimulae are piovided for the on-diagonal cells of the corresponding hat matrices Methods for identifying outliers are discussed.     

Teaching Survey Sampling Using Simulation

SURVEY is a computer program that simulates samples drawn from a hypothetical county. We use SURVEY in introductory and advanced sample survey classes to allow students to become involved in all stages of the sampling process, from designing the survey, to analyzing it, to dealing with nonresponse.     

Have children adapted to their mothers working, or was adaptation unnecessary? Cohort effects and the relationship between maternal employment and child well-being

Drawing on previous theoretical and empirical work, we posit that maternal employment influences on child well-being vary across birth cohorts. We investigate this possibility by analyzing longitudinal data from a sample of children and their mothers drawn from the National Longitudinal Survey of Youth. We introduce a series of age, cohort, and maternal employment interaction terms into multilevel models predicting child well-being to assess whether any potential short-term or long-term effects of early and current maternal employment vary across birth cohorts. Results indicate that maternal employment largely is inconsequential to child well-being regardless of birth cohort, with a few exceptions. For instance, children born in earlier cohorts may have experienced long-term positive effects of having an employed mother; however, as maternal employment became more commonplace in recent cohorts, these beneficial effects appear to have disappeared. We discuss theoretical and methodological implications of these findings.     

Regression models for cyclic data

Summary. Geologists take slices through rock samples at a series of different orientations. Each slice is examined for a phenomenon which may occur in one of two states labelled clockwise and anticlockwise. The probability of an occurrence being in the clockwise state is dependent on the orientation. Motivated by these data, two models are presented that relate the probability of an event to orientation. Each model has two parameters, one identifying the orientation corresponding to the peak probability, and the other controlling the rate of change of probability with orientation. One model is a logistic model, whereas the other involves a power of the sine function. For the given data neither model consistently outperforms the other.     

How to reduce the risk of HIV infection for the seriously mentally ill.

1. The professional literature increasingly indicates the need to educate persons with serious mental illness regarding HIV/AIDS. 2. Community-based organizations currently responding to the AIDS epidemic are poorly equipped to respond to the special needs of persons with serious mental illness. 3. Persons with serious mental illness are concerned by HIV/AIDS. Some, however, will incorporate education into their pathology via delusional systems or misunderstandings. 4. Effective programs for this population can be developed following community health nursing principles.