Asymptotic inference for mixture models by using data-dependent priors

For certain mixture models, improper priors are undesirable because they yield improper posteriors. However, proper priors may be undesirable because they require subjective input. We propose the use of specially chosen data-dependent priors. We show that, in some cases, data-dependent priors are the only priors that produce intervals with second-order correct frequentist coverage. The resulting posterior also has another interpretation: it is the product of a fixed prior and a pseudolikelihood.     

Some aspects of the reparametrization of statistical models

Definitions are given for orthogonal parameters in the context of Bayesian inference and likelihood inference. The exact orthogonalizing transformations are derived for both cases, and the connection between the two settings is made precise. These parametrizations simplify the interpretation of likelihood functions and posterior distributions. Further, they make numerical maximization and integration procedures easier to apply. Several applications are studied.     

Leisure Activities in Unemployed Emerging Adults: Links to Career Adaptability and Subjective Well‐Being

The present study examined if frequency and quality of 3 types of leisure activities (i.e., relaxation, achievement, and social) can function as protective factors for subjective well‐being (SWB) and career adaptability (CA) among 184 unemployed emerging adults (84 women, 100 men). Participants responded to measures of leisure frequency and quality, SWB, and CA. The results of a multivariate analysis of variance indicated that the frequency of relaxation, achievement, and social leisure activities had no effect on SWB and CA. However, regression analyses indicated that the quality of social leisure activities significantly predicted SWB and the quality of achievement and social leisure activities significantly predicted CA. The quality of relaxation leisure activities was not associated with SWB and CA. Findings indicate that counselors who work with unemployed emerging adults can use leisure activities to promote SWB and CA. Future research to better understand the role of leisure in well‐being and career development among emerging adults is encouraged.     

Bootstrap confidence interval estimates of cpk: an introduction

The interpretation of C_pk:, a common measure of process capability and confidence limits for it, is based on the assumption that the process is normally distributed. The non-parametric but computer intensive method called Bootstrap is introduced and three Bootstrap confidence interval estimates for C^ are defined. An initial simulation of two processes (one normal and the other highly skewed) is presented and discussed     

Sparse additive models

Summary.  We present a new class of methods for high dimensional non-parametric regression and classification called sparse additive models. Our methods combine ideas from sparse linear modelling and additive non-parametric regression. We derive an algorithm for fitting the models that is practical and effective even when the number of covariates is larger than the sample size. Sparse additive models are essentially a functional version of the grouped lasso of Yuan and Lin. They are also closely related to the COSSO model of Lin and Zhang but decouple smoothing and sparsity, enabling the use of arbitrary non-parametric smoothers. We give an analysis of the theoretical properties of sparse additive models and present empirical results on synthetic and real data, showing that they can be effective in fitting sparse non-parametric models in high dimensional data.     

Short run spc based upon the second order dynamic linear model for trend detection

Recently, several new applications of control chart procedures for short production runs have been introduced. Bothe (1989) and Burr (1989) proposed the use of control chart statistics which are obtained by scaling the quality characteristic by target values or process estimates of a location and scale parameter. The performance of these control charts can be significantly affected by the use of incorrect scaling parameters, resulting in either an excessive "false alarm rate," or insensitivity to the detection of moderate shifts in the process. To correct for these deficiencies, Quesenberry (1990, 1991) has developed the Q-Chart which is formed from running process estimates of the sample mean and variance. For the case where both the process mean and variance are unknown, the Q-chaxt statistic is formed from the standard inverse Z-transformation of a t-statistic. Q-charts do not perform correctly, however, in the presence of special cause disturbances at process startup. This has recently been supported by results published by Del Castillo and Montgomery (1992), who recommend the use of an alternative control chart procedure which is based upon a first-order adaptive Kalman filter model Consistent with the recommendations by Castillo and Montgomery, we propose an alternative short run control chart procedure which is based upon the second order dynamic linear model (DLM). The control chart is shown to be useful for the early detection of unwanted process trends. Model and control chart parameters are updated sequentially in a Bayesian estimation framework, providing the greatest degree of flexibility in the level of prior information which is incorporated into the model. The result is a weighted moving average control chart statistic which can be used to provide running estimates of process capability. The average run length performance of the control chart is compared to the optimal performance of the exponentially weighted moving average (EWMA) chart, as reported by Gan (1991). Using a simulation approach, the second order DLM control chart is shown to provide better overall performance than the EWMA for short production run applications     

Auditory–Visual Context and Memory Retrieval in 3‐Month‐Old Infants

In 3 experiments, 3‐month‐old infants were trained to move an overhead mobile by kicking 1 of their feet in the presence of a distinctive visual (crib bumpers) and auditory (music) context. In Experiment 1A, 5‐day but not 1‐day retention was disrupted if either or both elements of the context present during the retention test were novel. In Experiment 1B, 5‐day retention was observed when only a single component of the training context, visual or auditory, was present. In Experiment 2, the retention test occurred at 14 days but it was preceded 24 hr earlier by a brief reactivation treatment. When the reactivation treatment consisted of reexposing the infant to the training crib bumpers and music, or just to the training music, it was not successful. Reactivation was successful when the reactivation treatment consisted of only the training crib bumpers. These results indicate that, in this paradigm, 3‐month‐old infants do not encode the elements of the context holistically and that, following forgetting, the visual contextual cues become dominant over the auditory contextual cues in facilitating retrieval.     

Risk groups for parasuicide – a survey of unselected people who attempt suicide treated in hospital

A registration survey of parasuicide patients seeking hospital care in a defined catchment area was conducted over 24 months (1989-1990). In 1989, 475 individuals registered as residents in the catchment area were given care on 541 occasions, and in 1990, 382 individuals received care on 426 occasions as as a result of parasuicide. The parasuicide rates for the overall population in the catchment area were estimated by means of demographic variables. Parasuicide rates were highest among women 25-39 years old and among men 30-39 years old, i.e., in older age groups than previous studies (from the 1970s) have shown. Parasuicide rates are 3 times as high for single men as for married men and twice as high for single women as for married women. Among single men and women, divorcé(e)s show the highest parasuicide rates, especially in the 15-34 age group. The number of parasuicides among women decreased significantly between 1989 and 1990, which had the effect of evening out the female: male parasuicide ratio (1.28:1). Moreover, for the first time it becomes clear that the Finnish citizens in Sweden, both men and women, show a high risk for parasuicide compared with the Swedish population. These results focus attention on deficient psychic and social wellbeing of Finns in Sweden.