The effects of reinforced pretraining on subsequent rule discovery were examined with college students as subjects. Levels of behavioral stereotypy observed during reinforced and non-contingent pretraining were compared. During pretraining subjects received reinforcement if they pressed two keys in a particular sequence. During the problem session pressing each key four times was a necessary condition for reinforcement, but each problem had additional different requirements for reinforcement. Subjects were asked to solve the problems by discovering the rule that determined whether or not they received reinforcement. Levels of stereotyped responding during pretraining were equivalent for contingently and non-contingently trained subjects. During the problem session contingently pretrained, non-contingently pretrained, and naive subjects required equal numbers of trials to solve problems and solved the same number of problems. The results suggest that behavioral stereotypy observed in this experimental preparation may be due to repeated exposure to the task. Differences between the results observed in this study and that of Schwartz (1982) and implications for the use of reinforcement procedures in applied settings are discussed.
Summary. Although it has been widely accepted since the 1960s that smoking cigarettes carries a substantial health risk, worldwide mortality from tobacco-related diseases is increasing rapidly at the beginning of the 21st century. To provide the motivation to control this epidemic there is a continuing and pressing need for information on the risks of tobacco consumption that is accurate, up to date, locally relevant and imaginatively presented. 相似文献
This article considers optimal prediction of the finite population distribution function under Gaussian superpopulation models, which allows auxiliary prior information to be incorporated into the estimation process. Large sample approximations for the variance of the optimal predictors are derived in some special important cases. A small scale Monte Carlo study illustrates comparisons between the optimal predictor and some others which are proposed in the literature. The conclusion is that the optimal predictor can be considerably more efficient in situations where the normal superpopulation model is adequate. 相似文献
Clinical trials and other types of studies often examine the effects of a particular treatment or experimental condition on a number of different response variables. Although the usual approach for analysing such data is to examine each variable separately, this can increase the chance of false positive findings. Bonferroni's inequality or Hotelling's T2 statistic can be employed to control the overall type I error rate, but these tests generally lack power for alternatives in which the treatment improves the outcome on most or all of the endpoints. For the comparison of independent groups, O'Brien (1984) developed a rank-sum type test that has greater power than the Bonferroni and T2 procedures when one treatment is uniformly better (i.e. for all endpoints) than the other treatment(s). In this paper we adapt the rank-sum test to studies involving paired data and demonstrate that it, too, has power advantages for such alternatives. Simulation results are described, and an example from a study measuring the effects of sleep loss on glucose metabolism is presented to illustrate the methodology. 相似文献
This study used path analysis to examine the relationship between perceived barriers, acculturation, and role model influence on the career self‐efficacy and career considerations of a sample of Hispanic women. Two path models were examined. The male‐dominated model accounted for 15% of the variance, and the female‐dominated model accounted for 26% of the variance. No relationship was found between the variables of interest and male‐dominated career self‐efficacy and consideration. However, perceived barriers were related to female‐dominated career consideration and Anglo acculturation significantly contributed to female‐dominated career self‐efficacy. Results are discussed with regard to career practice and research with Hispanic women. 相似文献
In this article, we explore the wraparound approach of service delivery as a model for transnational social work. The wraparound model, used primarily within community‐based children's mental health services and child protection initiatives, has been effective when planning services for clients and their families with complicated needs, whose care has to be provided within a multiple provider context. Most social work is delivered nationally or internationally rather than trans‐nationally. In the article we outline how the model could be structured to meet the particular needs of transmigrants, including the involvement of NGOs and INGOs, and identify key obstacles and limitations. 相似文献
Summary. Olfactometer experiments are used to determine the effect of odours on the behaviour of organisms such as insects or nematodes, and typically result in data comprising many groups of small overdispersed counts. We develop a non-homogeneous Markov chain model for data from olfactometer experiments with parasitoid wasps and discuss a relation with the Dirichlet–multinomial distribution. We consider the asymptotic relative efficiencies of three different observation schemes and give an analysis of data intended to shed light on the effect of previous experience of odours in the wasps. 相似文献
SUMMARY This paper presents a design procedure for ChSP-4A(c1,c2)r plans based on Kullback-Leibler information and the minimum sum of risks. A table that gives the values of the parameters n and k indexed by the acceptable quality level (AQL) and limiting quality level (LQL) is presented, from which one can select a plan which gives a desired AQL and LQL when the producer's risk alpha= 0.05 and the consumer's risk beta = 0.10. A concluding remark for this series of five papers is given at the end of this paper. 相似文献
Audiotapes of the voices of77 preschool children were prepared. Subjects listened to the tapes, and then provided their impressions of the competence, leadership, dominance, warmth, and honesty of the children. Judgments of the voices' babyishness and attractiveness were also obtained. Perceivers reliably discriminated the children's voices along the dimensions of babyishness and attractiveness. Moreover, analyses revealed that the previously documented impact of these characteristics on first impressions of adults extends to impressions of young children. The similarity of the effects of these characteristics on impressions formed about children to those revealed for adults suggests that vocal qualities may have an impact on personality development via a process of self-fulfilling prophecy. 相似文献