The Rate of Convergence of some Asymptotic Expansions for Distribution Approximations via an Esseen Type Estimate

Some asymptotic expansions not necessarily related to the central limit theorem are studied. We first observe that the smoothing inequality of Esseen implies the proximity, in the Kolmogorov distance sense, of the distributions of the random variables of two random sequences satisfying a sort of general asymptotic relation. We then present several instances of this observation. A first example, partially motivated by the the statistical theory of high precision measurements, is given by a uniform asymptotic approximation to (g(X + μ _n )) _n∈?, where g is some smooth function, X is a random variable and (μ _n ) _n∈? is a sequence going to infinity; a multivariate version is also stated and proved. We finally present a second class of examples given by a randomization of the interesting parameter in some classical asymptotic formulas; namely, a generic Laplace's type integral, randomized by the sequence (μ _n X) _n∈?, X being a Gamma distributed random variable.     

Exercise can improve speed of behavior in older drivers

The main aim of this research was to study the effects of a specific exercise program on the speed of behavior of older adults during on-the-road driving. Twenty-six drivers (55-78 yr old) were randomly assigned to either an exercise group or a control group. The exercise program (3 sessions of 60 min/wk for 8 wk) incorporated tasks that induced the participants to respond quickly to challenging situations. On-the-road driving tasks (under single- and dual-task conditions) included measures of simple and choice reaction time, movement time, and response time. Significant positive effects were found at follow-up resulting from participation in the exercise program: Improvements were found for several measures in all driving tasks, and a composite score reflected a better general drivers' speed of behavior. These results show that exercise can enhance speed of behavior in older drivers and should therefore be promoted.     

An analysis of how children adapt to residential care

This research analyses the personal, social and educational adaptation of 74 children, aged between 6 and 18, under measures of protection in residential care centres. The Autoevaluative Multifactorial Child Adaptation Test (TAMAI) was applied to evaluate the children's level of adaptation. The study also aims to determine the relationship between the different levels of competence and/or functioning in the different areas of adaptation. The results indicate that institutionalised children show a high level of failure to adapt in both personal and social aspects. The fact that children show dissociative maladjustment, negative thoughts and mechanisms for escaping from reality (dreaming, negative opinion of self and undervaluing) is confirmed. There is evidence of the negative effects of neglect on children's perceptions, especially a poor opinion of self and inadequate self esteem. Worthy of note are a maladjusted opinion of self and of reality which makes them pile the tension, fear and uneasiness they live through upon their own shoulders, something which can lead to undervaluing. An inability to adapt to school life manifests itself in a low work level and low motivation to learn and a general dissatisfaction with their schooling situation.     

Cash Is King—How OBM Helped a North American Telecommunications Organization Obtain $76 Million in Receivables

Imagine a freshly formed team of people who are new to their jobs, assigned by top leadership to meet very ambitious targets in the mission-critical department that collects aged (past-due) payments from the company's largest accounts … (cue Mission Impossible theme). At a large telecommunications company in North America, the Senior Leadership Team led an effort to increase collections of aged receivables on its top accounts by $50 million from the previous year. Using OBM techniques, they surpassed the $50 million goal, reaching $76 million. The team also lowered the Days Sales Outstanding (DSO) by 8.5 days.     

Learning about migration decisions from the migrants: Using complementary datasets to model intra-regional migrations in Spain

We investigate the determinants of the remarkable increase in intra-regional migrations since the 1980's in Spain, using a large administrative micro dataset on migrants. Conditional migration probabilities are identified by comparing the migrants' joint distribution of characteristics to the corresponding distribution from the Spanish Labour Force Survey. The proportion of employment in the service industry, unemployment, house prices and education, all have an important positive effect on the individual probabilities of intra-regional migration. Received: 16 May 1999/Accepted: 26 September 2000     

Broadcasting standardisation: An analysis of the linguistic normalisation process in Murcian Spanish

The samples used from radio programme recordings have been demonstrated to be very useful sources for the study of styles and the analysis of linguistic variation and change. The aim of this paper is to show the results of a longitudinal study of Murcian speech carried out following a real-time approach with a retrospective trend design in order to detect and measure the apparent increasing diffusion of standard Castilian features from northern Peninsular Spanish over Murcian Spanish, a traditionally non-standard region. For this purpose, following the methodology used in similar studies, we focussed on the quantification of the level of standardisation of people interviewed in radio broadcasts in the last twenty-six years. In this way, the correlation of linguistic variables with social variables (groups) and time intervals, allowed us to compare and analyse the sociolinguistic behaviour of the different social groups in terms of standardisation (adoption of Castilian Spanish features) or non-standardisation (maintenance of local Murcian features) and trends.     

Influence diagnostics for the structural errors-in-variables model under the Student-t distribution

The influence of observations on the parameter estimates for the simple structural errors-in-variables model with no equation error, under the Student-t distribution, is investigated using the local influence approach. The main conclusion is that the Student-t model with small degrees of freedom is able to incorporate possible outliers and influential observations in the data. The likelihood displacement approach is useful for outlier detection, especially when a masking phenomenon is present and the degrees of freedom parameter is large. The diagnostics are illustrated with two examples.     

The attitudes toward lesbians and gay men scale (ATLG): adaptation and testing the reliability and validity in Chile

Previous researchers have used the attitudes toward lesbians and gay men (ATLG) scale (Herek, 1988) and reported their own reliability coefficients and validity measures, but research on this subject is scarce in Chile. In order to determine if ATLG scale was a reliable and valid instrument in our country, we adapted and examined the psychometrics properties using a sample composed of 142 psychology and economics undergraduate students. This study found the ATLG scale to be reliable (a = .90) and valid for the Chilean population and is a recommended instrument for measuring attitudes toward gay men and lesbians.