Ridge Regression: Degrees of Freedom in the Analysis of Variance

It appears to be common practice with ridge regression to obtain a decomposition of the total sum of squares, and assign degrees of freedom, according to established least squares theory. This discussion notes the obvious fallacies of such an approach, and introduces a decomposition based on orthogonality, and degrees of freedom based on expected mean squares, for non-stochastic k.     

On the poisson index of dispersion

A commonly used statistic for testing hypotheses concerning count data is the index of dispersion or variance test (c.f., Fisher 1950, Rao and Chakravarti 1956). The statistic is essentially the ratio of the sample variance to the sample mean,The hypothesis being tested is commonly referred to as the homogeneity hypothesis, often without further detailed specification. However, a closer study of the literature indicates that there are really two different hypotheses of interest.     

Measuring Sharedness of Team-Related Knowledge: Design and Validation of a Shared Mental Model Instrument

Many researchers have explored how people share and construct similar mental models in teams. They have claimed that successful team performance depends on a shared mental model of team members about task, team, equipment and situation. Most of the literature has illustrated simplified relationships between a team's mental model and their performance without a valid instrument addressing the confined and relevant constructs of a shared mental model. This paper describes the instrument development steps and the conceptual framework for factors associated with shared mental models. After development and refinement, the instrument was finalized for use to measure team-related knowledge. The final instrument consists of 42 items that are linked to the five emergent factors of shared mental models including general task and team knowledge, general task and communication skills, attitude toward teammates and task, team dynamics and interactions, and team resources and working environment.     

Personality and Subjective Well-Being: Evidence from South Korea

Although the statistically significant relationship between personality traits and subjective well-being (i.e., self-reported happiness and life satisfaction) is well-known in the field of positive psychology, some scholars still cast doubt on the external validity of this finding and the strength of personality dimensions vis-à-vis other individual-level determinants of subjective well-being such as income, employment status, marital status, self-reported health, and so on. Using a nationally representative, face-to-face survey fielded in South Korea in 2009, we find that personality traits (measured by the Five-factor Model)—particularly, Emotional Stability and Extraversion—are positively associated with happiness and life satisfaction, after controlling for other covariates. The effects of personality traits are often on par with, and sometimes even greater than, those of other well-known determinants.     

Classroom sex composition and first-grade school outcomes: The role of classroom behavior

Using nationally representative data from the Early Childhood Longitudinal Study-Kindergarten Cohort (N = 21,409; 10,452 girls and 10,957 boys; mean age = 7.24 years), the association between first-grade classroom sex composition (CSC), measured as the percentage of female students, and end of the year academic (reading, mathematics) and socio-emotional (externalizing problems, internalizing problems, self-control, interpersonal skills) outcomes was examined. Using multilevel modeling techniques and controlling for prior achievement levels, CSC was positively associated with children’s reading achievement at the end of first grade; students performed better in reading in classes with a higher percentage of female students. CSC was also associated with three of the socio-emotional outcomes; controlling for prior levels, students in classrooms with a higher percentage of girls had better self-control and interpersonal skills and fewer internalizing problems. Classroom behavior mediated the effects of CSC on reading achievement and the socio-emotional outcomes. Implications for the composition of first-grade classrooms are discussed.     

Writing the self: Exploring the stigma of hearing impairment

Neoclassical economic and sociological views of discrimination are compared. We summarize economic models of taste, statistical, error, and monopolistic discrimination. Economists argue that competitive market forces should lead to the demise of discrimination in the long run. After explaining these arguments, we present sociological arguments about institutional and social‐psychological mechanisms that promote the persistence of discrimination. A typology of social‐psychological feedback effects from discrimination is presented. We conclude that it is important to recognize forces promoting both the erosion and persistence of discrimination and that this requires a perspective drawing upon both sociology and economics.     

Cast in a racial mould

Women of Phokeng: Consciousness, Life Strategy, and Migrancy in South Africa 1900 ‐1983 by Belinda Bozzoli, with the assistance of Mmantho Nkotsoe, Johannesburg, Ravan Press, 1991.

Our Precious Metal: African Labour in South Africa's Gold Industry, 1970–1990 by Wilmot G. James, David Philip, James Currey &; Indiana University Press, Cape Town, London &; Bloomington,1992.

Bounds of Possibility ‐ The Legacy of Steve Biko &; Black Consciousness by N.B. Pityana, M. Ramphele, M. Mpumlwana, &; L. Wilson, (eds), Cape Town, David Philip, 1991.

Faces in the revolution: the psychological effects of violence on township youth in South Africa by Gill Straker, with Fathima Moosa, Rise Becker and Madiyoyo Nkwale. Cape Town, David Philip, 1992 and Athens, Ohio, Ohio University Press, 1992.

Lives of Courage: Women for a New South Africa by Diana E.H.Russell. New York, Basic Books, 1989.

Towards Justice? Crime and State Control in South Africa by Desiree Hansson and Dirk van Zyl Smit (eds), Cape Town, Oxford University Press, 1990.

South Africa in the Nineties by DJ van Vuuren, NE Wiehahn, NJ Rhoodie en M Wiechers (eds), HSRC Publishers, 1991.

To Live in Fear: Witchburning and Medicine Murder in Venda by A de V. Minnar, D Offringa and C Payze, HSRC, Pretoria, 1992.

The Anti‐Politics Machine: ‘Development’, Depoliticization and Bureaucratic Power by James Ferguson, Cambridge, Cambridge University Press, 1990.

Zimbabwe's Guerrilla War: Peasant Voices by Norma J. Kriger. Cambridge University Press, African Studies Series, number 70,1992.

A Passage to England ‐ Barbadian Londoners speak of home by John Western. U.C.L. Press, London, 1992.

Breaking the formal frame: Readings in South African education in the eighties by Clive Millar, Sarah‐Anne Raynham and Angela Schaffer (eds). Cape Town: Oxford University Press, 1991.

Negotiation : Theories, Strategies and Skills by Wynand Pienaar and Manie Spoelstra, Kenwyn, Juta, 1991

SUM: Selected Works by Martin Versveld. Cape Town: Carrefour Press 1991.

Projections in the Past Tense, by Kelwyn Sole. Ravan Press, 1992.     

The Detection of Influential Observations for Allocation,Separation, and the Determination of Probabilities in a Bayesian Framework

Normal theory separation and allocation problems are discussed from a predictive point of view. Influence statistics are defined and employed to ascertain the impact that particular observations will have on the inferential goals—allocation of future observations, separation between populations, and the determination of probabilities for future cases. Methods are illustrated on a collection of financial data taken from Johnson and Wichern (1982).