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31.
Despite its importance, there has been little attention in the modeling of time series data of categorical nature in the recent past. In this paper, we present a framework based on the Pegram's [An autoregressive model for multilag Markov chains. Journal of Applied Probabability 17, 350–362] operator that was originally proposed only to construct discrete AR(p) processes. We extend the Pegram's operator to accommodate categorical processes with ARMA representations. We observe that the concept of correlation is not always suitable for categorical data. As a sensible alternative, we use the concept of mutual information, and introduce auto-mutual information to define the time series process of categorical data. Some model selection and inferential aspects are also discussed. We implement the developed methodologies to analyze a time series data set on infant sleep status. 相似文献
32.
Atanu Biswas Rahul Bhattacharya Taranga Mukherjee 《Journal of the Korean Statistical Society》2019,48(4):524-536
A multi-arm response-adaptive allocation design is developed for circular treatment outcomes. Several exact and asymptotic properties of the design are studied. Stage-wise treatment selection procedures based on the proposed response-adaptive design are also suggested to exclude the worse performing treatment(s) at earlier stages. Detailed simulation study is carried out to evaluate the proposed selection procedures. The applicability of the proposed methodologies is illustrated through a real clinical trial data on cataract surgery. 相似文献
33.
Uttam Bandyopadhyay Atanu Biswas Shirsendu Mukherjee 《Statistical Methods and Applications》2009,18(1):13-33
Adaptive designs are sometimes used in a phase III clinical trial with the goal of allocating a larger number of patients
to the better treatment. In the present paper we use some adaptive designs in a two-treatment two-period crossover trial in
the presence of possible carry-over effects, where the treatment responses are binary. We use some simple designs to choose
between the possible treatment combinations AA, AB, BA or BB. The goal is to use the better treatment a larger proportion
of times. We calculate the allocation proportions to the possible treatment combinations and their standard deviations. We
also investigate related inferential problems, for which related asymptotics are derived. The proposed procedure is compared
with a possible competitor. Finally we use real data sets to illustrate the applicability of our proposed design. 相似文献
34.
This paper examines some non‐parametric group sequential designs applicable for randomized clinical trials, for comparing two continuous treatment effects taking the observations in matched pairs, or applicable in event‐based analysis. Two inverse binomial sampling schemes are considered, of which the second one is an adaptive data‐dependent design. These designs are compared with some fixed sample size competitors. Power and expected sample sizes are calculated for the proposed procedures. 相似文献
35.
Animikh Biswas 《统计学通讯:理论与方法》2013,42(7):1293-1307
This work concerns the estimation of a smooth survival function based on doubly censored data. We establish strong consistency and asymptotic normality for a kernel estimator. Moreover, we also obtain an asymptotic expression for the mean integrated squared error, which yields an optimum bandwidth in terms of readily estimable quantities. 相似文献
36.
As the HIV/AIDS global pandemic continues to grow through a third decade, the need for social work educators to prepare social workers in distinct fields of practice with skills to assist those infected with and affected by HIV is of paramount importance. HIV/AIDS holds multi-level and multi-system effects for vulnerable populations. This article features global HIV and AIDS teaching resources beginning with common global practice challenges. Next, five teaching units focus on practice needs and challenges of divergent vulnerable populations including men who have sex with men, women, injecting drug users (IDU), commercial sex workers, and children orphaned by AIDS. Discussion questions, selected readings and electronic resources accompany each unit. The authors close the article with suggested recommendations for content integration into social work courses, and next steps for the profession. 相似文献
37.
Amrita Biswas 《统计学通讯:理论与方法》2013,42(5):920-933
The author considers the problem of finding designs insensitive to the presence of an outlier in a treatment-control block design setup for estimating the set of elementary contrasts between the effects of each test treatment and a control treatment. The criterion of robustness suggested by Mandal (1989) in block design setup for estimating a full set of orthonormal treatment contrasts is adapted. A new class viz. partially balanced treatment incomplete block designs (PBTIBD) is introduced and it is shown that balanced treatment incomplete block designs (BTIBD) and PBTIB designs, under certain conditions, are robust in the previous sense. Such designs are important in the sense that the inference on the treatment contrasts under consideration remain unaffected by the presence of an outlier. 相似文献
38.
Compound optimal designs are considered where one component of the design criterion is a traditional optimality criterion such as the D‐optimality criterion, and the other component accounts for higher efficacy with low toxicity. With reference to the dose‐finding problem, we suggest the technique to choose weights for the two components that makes the optimization problem simpler than the traditional penalized design. We allow general bivariate responses for efficacy and toxicity. We then extend the procedure in the presence of nondesignable covariates such as age, sex, or other health conditions. A new breast cancer treatment is considered to illustrate the procedures. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
39.
While analyzing 2 × 2 contingency tables, the log odds ratio for measuring the strength of association is often approximated
by a normal distribution with some variance. We show that the expression of that variance needs to be modified in the presence
of correlation between two binomial distributions of the contingency table. In the present paper, we derive a correlation-adjusted
variance of the limiting normal distribution of log odds ratio. We also propose a correlation adjusted test based on the standard
odds ratio for analyzing matched-pair studies and any other study settings that induce correlated binary outcomes. We demonstrate
that our proposed test outperforms the classical McNemar’s test. Simulation studies show the gains in power are especially
manifest when sample size is small and strong correlation is present. Two examples of real data sets are used to demonstrate
that the proposed method may lead to conclusions significantly different from those reached using McNemar’s test. 相似文献
40.
Dey & Midha (1996) showed that some of the complete diallel crosses plans, obtained by using triangular partially balanced designs with two associate classes, are optimal. In this investigation, it is derived that these optimal designs for diallel crosses are robust also against the unavailability of one block. 相似文献