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1.
Ingeborg Küchler 《Statistics》2013,47(2):227-230
The Sequential Probaility Ratio Test is applied to test two simple hypotheses about the transition probability matrix of an irreducible homogeneous MARKOV chain with finite state space. An analogue (14) of Wald's Fundamental Identity, the Operating Characteristic Function (20-21) and the Average Sample Number (22-23) are given. These statements are generalizations of the MARKOV chain as well as some more conditions about the eigenvalues of the transition probability matrix. 相似文献
2.
Lund I 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2007,23(4):409-419
The study takes a closer look at at-risk gamblers, with the objective to see how they differ from no-risk gamblers. The data
comes from a national gambling survey in 2002, and the age group is 15–74 years. The sample consists of 4188 current gamblers
with no current gambling problems or pathology. The analysis includes cross-tabulations and a logistic regression. The results
show that at-risk gamblers differed substantially from no-risk gamblers in terms of demographic characteristics, gambling
behaviour and the presence of other assumed risk factors. Demographic segments with a higher risk of falling into the at-risk
group are men, young people, divorced or single people, and non-western immigrants. Furthermore, gambling problems in the
family, beginners luck and misconceptions about winning chances significantly increased the odds for at-risk gambling. The
study concludes that at-risk gamblers deserve more attention from research, that their similarity with problem gamblers increases
the likelihood that many of them will eventually develop a gambling problem, and that their tendency to be superstitious about
winning chances might be exploited in preventive work. 相似文献
3.
Estimates of subgroup treatment effects in overall nonsignificant trials: To what extent should we believe in them? 下载免费PDF全文
Julien Tanniou Ingeborg van der Tweel Steven Teerenstra Kit C.B. Roes 《Pharmaceutical statistics》2017,16(4):280-295
In drug development, it sometimes occurs that a new drug does not demonstrate effectiveness for the full study population but appears to be beneficial in a relevant subgroup. In case the subgroup of interest was not part of a confirmatory testing strategy, the inflation of the overall type I error is substantial and therefore such a subgroup analysis finding can only be seen as exploratory at best. To support such exploratory findings, an appropriate replication of the subgroup finding should be undertaken in a new trial. We should, however, be reasonably confident in the observed treatment effect size to be able to use this estimate in a replication trial in the subpopulation of interest. We were therefore interested in evaluating the bias of the estimate of the subgroup treatment effect, after selection based on significance for the subgroup in an overall “failed” trial. Different scenarios, involving continuous as well as dichotomous outcomes, were investigated via simulation studies. It is shown that the bias associated with subgroup findings in overall nonsignificant clinical trials is on average large and varies substantially across plausible scenarios. This renders the subgroup treatment estimate from the original trial of limited value to design the replication trial. An empirical Bayesian shrinkage method is suggested to minimize this overestimation. The proposed estimator appears to offer either a good or a conservative correction to the observed subgroup treatment effect hence provides a more reliable subgroup treatment effect estimate for adequate planning of future studies. 相似文献
4.
In observational studies, the overall aim when fitting a model for the propensity score is to reduce bias for an estimator of the causal effect. To make the assumption of an unconfounded treatment plausible researchers might include many, possibly correlated, covariates in the propensity score model. In this paper, we study how the asymptotic efficiency of matching and inverse probability weighting estimators for average causal effects change when the covariates are correlated. We investigate the case with multivariate normal covariates, a logistic model for the propensity score and linear models for the potential outcomes and show results under different model assumptions. We show that the correlation can both increase and decrease the large sample variances of the estimators, and that the correlation affects the asymptotic efficiency of the estimators differently, both with regard to direction and magnitude. Moreover, the strength of the confounding towards the outcome and the treatment plays an important role. 相似文献
5.
Ingeborg Stiefel Poppy Harris Julie A.
Rohan 《Australian and New Zealand Journal of Family Therapy》1998,19(2):55-62
In recent years there has been a renewed interest in psychodynamic ideas within the family therapy literature. While some authors have explored the usefulness of psychodynamic concepts in the systemic context (Byng-Hall, 1995; Flaskas, 1993, 1996; Luepnitz, 1988, 1997), others have argued that psychodynamic models of family therapy should be given more credence in systemic work with families (Guttman, 1991). This paper describes Object Relations Family Therapy (ORFT), a psychoanalytic model of family therapy, in plain English in order to minimise the obscurity of some of the existing terminology and to emphasise the utility of more contemporary formulations. ORFT addresses the interface between psychoanalytic and systemic theories. It offers a way of conceptualising complex family dynamics at both the interpersonal and intrapsychic levels. It also integrates an understanding of nonverbal, unstated and often implicit processes in its formulation of problem development. The unique contribution of ORFT is elaborated using a clinical example. 相似文献
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7.
Ingeborg Stiefel Philomena Renner 《Australian and New Zealand Journal of Family Therapy》2004,25(2):84-93
Parents of children with defiant behaviour are frequently encouraged to establish clear behavioural expectations and consistency. Yet parental exhaustion, the constancy of the child's demands, and the child's push for control may compromise the success of the behavioural approach, leaving the family and therapist to search for other methods. This paper introduces parenting strategies developed as part of the ‘C Plus C — K Program’ for parents of primary school aged children (age range 5–12 years) with major behavioural problems. The program encourages parents to utilise relationship‐building parenting strategies. It is anticipated that over time, the child will develop self‐regulatory ability in situations of stress, leading to a reduction in problem behaviour. Preliminary data suggests that the program may be effective in achieving this aim. C Plus C strategies are illustrated with a fictional vignette based on common parenting situations. 相似文献
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9.
T res Theorell Kristina Orth-Gom r Vanja Moser Anna-Lena Und n Ingeborg Eriksson 《Work and stress》1995,9(1):67-76
An intervention consisting of a thorough examination of the psychological worksite problems and a follow-up with feedback and recommendations was made in four different office worksites. One of the sites («active» group) was more organizational change-oriented than the others («passive» group). The course was followed before, three times during the 3 months of the intervention, and 4 months after the end of it, by means of three endocrine plasma markers: cortisol, prolactin and testosterone. In both study groups the prolactin levels increased in women during the starting phase of the intervention, whereas in men prolactin levels remained stable with a tendency (p=0.06) towards lowered prolactin levels during the end phase of the intervention in the active group. Cortisol levels increased markedly in the passive group and tended to decrease in the active group during the intervention (two-way interaction p=0.003), particularly in men. These findings may be indicative of feelings of uneasiness. Testosterone increased in the active group only, particularly at the beginning of the intervention and particularly in women, and also increased in a non-intervention control group. Testosterone levels are associated with anabolic activity. An increase may be indicative of a «placebo effect» of the intervention. Testosterone changes were still clearly observable after 4 months. 相似文献
10.
Ingeborg Stiefel Jane Carpenter Priscilla Liu Shaune Meyer Margaret Hamilton 《Australian and New Zealand Journal of Family Therapy》2004,25(2):116-117
Perhaps we should take a deep breath! We have successfully gained approval from three Area Health regions for a multi‐centre study, which assesses the effectiveness of a group program for parents of children with challenging behaviour. Each Ethics Committee had to have its say, and change a few things, but we were able to jump their hurdles without (we thought) over‐complicating a relatively no‐frills project. We were also extremely lucky that the project had received funding from the Centre for Mental Health. Without funding, it would have been difficult to afford essential research goodies, such as questionnaires at $2.50 per form, or even paper, adding up to several thousand dollars. 相似文献