Joint probability of statistical success of multiple phase III trials

In drug development, after completion of phase II proof‐of‐concept trials, the sponsor needs to make a go/no‐go decision to start expensive phase III trials. The probability of statistical success (PoSS) of the phase III trials based on data from earlier studies is an important factor in that decision‐making process. Instead of statistical power, the predictive power of a phase III trial, which takes into account the uncertainty in the estimation of treatment effect from earlier studies, has been proposed to evaluate the PoSS of a single trial. However, regulatory authorities generally require statistical significance in two (or more) trials for marketing licensure. We show that the predictive statistics of two future trials are statistically correlated through use of the common observed data from earlier studies. Thus, the joint predictive power should not be evaluated as a simplistic product of the predictive powers of the individual trials. We develop the relevant formulae for the appropriate evaluation of the joint predictive power and provide numerical examples. Our methodology is further extended to the more complex phase III development scenario comprising more than two (K > 2) trials, that is, the evaluation of the PoSS of at least k₀ () trials from a program of K total trials. Copyright © 2013 John Wiley & Sons, Ltd.     

A Multiple Three-Decision Procedures for Comparing Several Treatments with a Control Under Heteroscedasticity

In this article, the design-oriented two-stage multiple three-decision procedure is proposed to classify a set of normal populations with respect to a control under heteroscedasticity. The statistical tables of percentage points and the power-related design constants, to implement our new two-stage procedure, are given. Sometimes when the sample for the second stage is not available, the one-stage data analysis procedure is proposed. Classifying a treatment better than control when it is actually worse (and vice versa) is known as type III error. Both the two-stage and one-stage procedures control the type III error rate at a specified level. The relationship between the two-stage and one-stage procedures is discussed. Finally, the application of the proposed procedures is illustrated with an example.     

Approximate mrpp p-values obtained from four exact moments

A F0RTRAN-77 subroutine for a general version of multi-response permutation procedures (MRPP) is described. The exact four moments are employed in conjunction with the Pearson type I, type III, and type VI distributions to calculate the associated P-values.     

Main effect plan for 2m factorials which allow search and estimation of one unknown effect

In this paper, we discuss resolution III plans for 2^m factorial experiments which have an additional property. We relax the classical assumption that all the interactions are negligible by assuming that (at most) one of them may be nonnegligible. Which interaction is nonnegligible is unknown. We discuss designs which allow the search and estimation of this interaction, along with the estimation of the general mean and the main effects as in the classical resolution III designs.     

关于银行监管的博弈与思考--《新巴塞尔协议》的视角

2003年4月29日,巴塞尔委员会公布了新资本协议第三次征求意见稿,新协议对各国商业银行和政府监管当局提出了更多的挑战。本文运用博弈论的知识,从新巴塞尔协议的视角,对商业银行的监管进行了分析,并针对中国情况进行了讨论。     

新喀里多尼亚独立历程及前景分析

新喀里多尼亚是法国具有特殊地位的海外属地,其被殖民统治已经有150多年。本土原住民卡纳克人一直坚持斗争以寻求民族解放和国家独立,与欧洲移民形成严重的对立,暴力冲突时有发生。《马提翁协议》和《努美阿协议》的签署奠定了政治解决新喀里多尼亚问题的基础,法国政府将逐渐向新喀里多尼亚政府移交权力。当前,新喀里多尼亚政府已经可以行使除司法、公共安全、防务、货币、部分外交权以外的国家权力,民族独立指日可待。     

我国房地产业持续发展的政策环境及对策研究

美国次级债引发的全球金融危机和经济危机已对我国房地产经济产生了负面侵袭,渐强的不利局面与近几年来广为业内外人士诟病的＂房地产泡沫＂现象再度成为政府、专家、业内人士和普通消费者关注的议题。逆流之下,房地产业要转＂危＂为＂机＂,必须因势制宜,在不断变革中形成新的市场结构和制衡机制。     

The Detection of Nonnegligible Directional Effects With Associated Measures of Statistical Significance

ABSTRACT

When comparing two treatment groups, the objectives are often to (1) determine if the difference between groups (the effect) is of scientific interest, or nonnegligible, and (2) determine if the effect is positive or negative. In practice, a p-value corresponding to the null hypothesis that no effect exists is used to accomplish the first objective and a point estimate for the effect is used to accomplish the second objective. This article demonstrates that this approach is fundamentally flawed and proposes a new approach. The proposed method allows for claims regarding the size of an effect (nonnegligible vs. negligible) and its nature (positive vs. negative) to be made, and provides measures of statistical significance associated with each claim.     

Estimation of the Burr type III distribution with application in unified hybrid censored sample of fracture toughness

In this paper, the statistical inference of the unknown parameters of a Burr Type III (BIII) distribution based on the unified hybrid censored sample is studied. The maximum likelihood estimators of the unknown parameters are obtained using the Expectation–Maximization algorithm. It is observed that the Bayes estimators cannot be obtained in explicit forms, hence Lindley's approximation and the Markov Chain Monte Carlo (MCMC) technique are used to compute the Bayes estimators. Further the highest posterior density credible intervals of the unknown parameters based on the MCMC samples are provided. The new model selection test is developed in discriminating between two competing models under unified hybrid censoring scheme. Finally, the potentiality of the BIII distribution to analyze the real data is illustrated by using the fracture toughness data of the three different materials namely silicon nitride (Si₃N₄), Zirconium dioxide (ZrO₂) and sialon (Si_6?xAl_xO_xN_8?x). It is observed that for the present data sets, the BIII distribution has the better fit than the Weibull distribution which is frequently used in the fracture toughness data analysis.