Statistical analysis of intercropping data using a correlated error structure *

Intercropping is an important farming system, especially in tropical regions. A statistical model with competition coefficients and correlated error structure is suggested for the analysis of data from intercropping experiments involving two crop species. Data from an intercropping experiment with pearl millet and sorghum genotypes are used to illustrate the technique.     

Statistical Issues in Macroeconomic Modelling*

The paper describes the influx of mathematical statistics in economics. It focuses on an approach to macroeconometric modelling which is based on fundamental statistical concepts like the joint distribution function of all observable variables for the whole sample period. The methodology relies on valid conditioning and marginalization of this function in order to arrive at tractable subsystems, which can be analysed with statistical methods. Two case studies—the modelling of the household sector and of wages and prices in the Norges Bank RIMINI model—highlight this.     

Statistical Issues in Weather Forecasting*

Research and operational applications in weather forecasting are reviewed, with emphasis on statistical issues. It is argued that the deterministic approach has dominated in weather forecasting, although weather forecasting is a probabilistic problem by nature. The reason has been the successful application of numerical weather prediction techniques over the 50 years since the introduction of computers. A gradual change towards utilization of more probabilistic methods has occurred over the last decade; in particular meteorological data assimilation, ensemble forecasting and post‐processing of model output have been influenced by ideas from statistics and control theory.     

Statistical science and effective scientific communication*

Modern science increasingly uses sophisticated statistical techniques, yet papers in scientific journals are often defective in identification of methods used and in clear presentation of quantitative conclusions. The omission of essential information, ambiguities and misleading conclusions from ill-chosen methods often escape editorial challenge: referees, usually chosen for expertise in the substantive subject matter, may lack the statistical skill and experience needed for critical assessment. This paper makes proposals that might enable an editor and his referees more readily to detect the need for major revision before publication. Some matters have ethical components in addition to their implications for the advancement of knowledge in many disciplines.     

Statistical Issues in Fisheries' Stock Assessments*

Decisions concerning the management of fisheries are founded on confidence statements for interest parameters such as biomass and exploitation rate, derived from complex structural models that describe the dynamics of fisheries. We identify four generic statistical issues and focus on how they impact on the reliability of those confidence statements: (a) parameters for which the data have little or no information; (b) competing structural relationships; (c) weighting of observations; and (d) alternative methods for computing confidence statements. Our purpose is to give an exposition of how these issues impact on fisheries' analyses, with the intent of stimulating thought on more effective alternatives. We describe the fisheries' management context and use two specific studies to illustrate how these generic statistical issues impact on fisheries assessment results. It is demonstrated that these statistical issues can have a profound impact on fishery management decisions and that established approaches to handle them have not been fully developed.     

Statistical and Combinatorial Aspects of Comparative Genomics*

Abstract. This document presents a survey of the statistical and combinatorial aspects of four areas of comparative genomics: gene order based measures of evolutionary distances between species, construction of phylogenetic trees, detection of horizontal transfer of genes, and detection of ancient whole genome duplications.     

Statistical Genetics and Genetical Statistics: a Forensic Perspective*

This review paper focuses on forensic aspects of the relation between statistics and genetics. Some of the scientific achievements of the Swedish psychiatrist and geneticist Erik Essen‐Möller may be viewed in the above interdisciplinary context. In a number of situations the correct familial relation between a group of individuals is required. We discuss recent work done to relax some assumptions involved in the classical calculations in 10 ). Moreover, we extend the discussion to identification problems. In a given case there may be a large number of possible family constellations or pedigrees. A prior probability distribution is established. The posterior model accounts for the combinatorial complexities of the pedigrees, mutations, kinship, and uncertainty in allele frequencies. Examples are based on the shareware program FAMILIAS, see http://www.nr.no/familias . A main message of the present paper is that the Bayesian approach is a convenient framework to down‐weight unreasonable (e.g. incestuous) pedigrees that may always appear likely if only DNA‐measurements are used.     

中国古代的统计分析

利用统计和其他有关资料 ,对经济、社会问题进行分析 ,是中国古代统计思想的一个突出方面。中国古代的统计分析约始于春秋战国时期。《管子》① 书里就记载着很多统计分析的事例。管仲善于利用统计调查的成果 ,进行对比分析 ,来阐明事物与事物之间的关系。他在论述有关问题时 ,对土地与人口的关系 ,物价、生产与需求的关系 ,收入与消费 ,财富与所得的关系 ,等等进行了广泛、深入的分析。例如 ,他在《管子·治国》中认为农业收获有季节性 ,因此 ,在非收获季节向农民课税摊派 ,就会迫使他们求贷于高利贷者。对此 ,管仲进行了详尽的分析 :“凡…     

Statistical analysis for rounded data

When random variables do not take discrete values, observed data are often the rounded values of continuous random variables. Errors caused by rounding of data are often neglected by classical statistical theories. While some pioneers have identified and made suggestions to rectify the problem, few suitable approaches were proposed. In this paper, we propose an approximate MLE (AMLE) procedure to estimate the parameters and discuss the consistency and asymptotic normality of the estimates. For our illustration, we shall consider the estimates of the parameters in AR(p)$\mathit{AR}(p)$ and MA(q)$\mathit{MA}(q)$ models for rounded data.     

Statistical properties of detrended fluctuation analysis

The main goal of this work is to consider the detrended fluctuation analysis (DFA), proposed by Peng et al. [Mosaic organization of DNA nucleotides, Phys. Rev. E. 49(5) (1994), 1685–1689]. This is a well-known method for analysing the long-range dependence in non-stationary time series. Here we describe the DFA method and we prove its consistency and its exact distribution, based on the usual i.i.d. assumption, as an estimator for the fractional parameter d. In the literature it is well established that the nucleotide sequences present long-range dependence property. In this work, we analyse the long dependence property in view of the autoregressive moving average fractionally integrated ARFIMA(p, d, q) processes through the analysis of four nucleotide sequences. For estimating the fractional parameter d we consider the semiparametric regression method based on the periodogram function, in both classical and robust versions; the semiparametric R/S(n) method, proposed by Hurst [Long term storage in reservoirs, Trans. Am. Soc. Civil Eng. 116 (1986), 770–779] and the maximum likelihood method (see [R. Fox and M.S. Taqqu, Large-sample properties of parameter estimates for strongly dependent stationary Gaussian time series, Ann. Statist. 14 (1986), 517–532]), by considering the approximation suggested by Whittle [Hypothesis Testing in Time Series Analysis (1953), Hafner, New York].     

Statistical pattern recognition in image analysis

Many tasks in image analysis can be formulated as problems of discrimination or, generally, of pattern recognition. A pattern-recognition system is normally considered to comprise two processing stages: the feature selection and extraction stage, which attempts to reduce the dimensionality of the pattern to be classified, and the classification stage, the purpose of which is to assign the pattern into its perceptually meaningful category. This paper gives an overview of the various approaches to designing statistical pattern recognition schemes. The problem of feature selection and extraction is introduced. The discussion then focuses on statistical decision theoretic rules and their implementation. Both parametric and non-parametric classification methods are covered. The emphasis then switches to decision making in context. Two basic formulations of contextual pattern classification are put forward, and the various methods developed from these two formulations are reviewed. These include the method of hidden Markov chains, the Markov random field approach, Markov meshes, and probabilistic and discrete relaxation.     

Statistical pattern recognition in image analysis

Many tasks in image analysis can be formulated as problems of discrimination or, generally, of pattern recognition. A pattern-recognition system is normally considered to comprise two processing stages: the feature selection and extraction stage, which attempts to reduce the dimensionality of the pattern to be classified, and the classification stage, the purpose of which is to assign the pattern into its perceptually meaningful category. This paper gives an overview of the various approaches to designing statistical pattern recognition schemes. The problem of feature selection and extraction is introduced. The discussion then focuses on statistical decision theoretic rules and their implementation. Both parametric and non-parametric classification methods are covered. The emphasis then switches to decision making in context. Two basic formulations of contextual pattern classification are put forward, and the various methods developed from these two formulations are reviewed. These include the method of hidden Markov chains, the Markov random field approach, Markov meshes, and probabilistic and discrete relaxation.     

Statistical evidence in contingency tables analysis

The likelihood ratio is used for measuring the strength of statistical evidence. The probability of observing strong misleading evidence along with that of observing weak evidence evaluate the performance of this measure. When the corresponding likelihood function is expressed in terms of a parametric statistical model that fails, the likelihood ratio retains its evidential value if the likelihood function is robust [Royall, R., Tsou, T.S., 2003. Interpreting statistical evidence by using imperfect models: robust adjusted likelihood functions. J. Roy. Statist. Soc. Ser. B 65, 391–404]. In this paper, we extend the theory of Royall and Tsou [2003. Interpreting statistical evidence by using imperfect models: robust adjusted likelihood functions. J. Roy. Statist. Soc., Ser. B 65, 391–404] to the case when the assumed working model is a characteristic model for two-way contingency tables (the model of independence, association and correlation models). We observe that association and correlation models are not equivalent in terms of statistical evidence. The association models are bounded by the maximum of the bump function while the correlation models are not.     

官方统计机构的统计分析工作

在一些国家 ,官方统计机构的职能只限于统计数据信息的收集、整理和出版 ;而在另外一些国家 ,统计分析工作也同时明确在它们的职能范围内。法国就属于后一类国家。法国国家统计局 ,即法国统计及经济研究所 ,简称ＩＮＳＥＥ———从名称上就能看出其统计分析职能的存在。法国于 194 6年 6月 14日颁布的有关《建立国家统计局》的法律条文 ,明确地将统计分析工作规定在ＩＮＳＥＥ的职能范围内。本文的撰写目的是 ,就统计分析工作在官方统计机构中所占的地位以及所扮演的角色展开讨论 ,即 :这些机构是否应将相当一部分的人力、物力投入到统计分…     

Statistical theory of the analysis of experimental designs

(Abstracts of papers presented at the Annual Meeting of the Statistical Science Association of Canada; May 29, 30, 31, 1975. / R$eAsum$eAs des articles pr$eAsent$eAs au congres annuel; 29, 30, 31 mai 1975; University of Alberta, Edmonton, Alberta.)     

我国居民收入分配格局的统计分析

一、引言收入分配方式与结果影响和制约社会经济的有序发展。经过 2 0多年的改革 ,我国居民收入分配格局发生了很大变化。特别是收入差距拉大引起人们关注。本文对这个问题进行统计分析并指出其政策意义。　　二、改革以来居民收入分配格局的基本情况　　改革以前我国均等化程度很高 ,文献表明当时城市基尼系数在 0 2以下 ,农村多数估计都在 0 2 1— 0 2 4之间。而许多发展中国家 ,城市基尼系数在 0 37— 0 43之间 ,农村基尼系数则在 0 34— 0 40之间 ,我国显然比世界上大多数发展中国家都要低。这主要是由于收入分配中强调公平而忽…     

Statistical aspects of linkage analysis in interlaboratory studies

This paper investigates statistical issues that arise in interlaboratory studies known as Key Comparisons when one has to link several comparisons to or through existing studies. An approach to the analysis of such a data is proposed using Gaussian distributions with heterogeneous variances. We develop conditions for the set of sufficient statistics to be complete and for the uniqueness of uniformly minimum variance unbiased estimators (UMVUE) of the contrast parametric functions. New procedures are derived for estimating these functions with estimates of their uncertainty. These estimates lead to associated confidence intervals for the laboratories (or studies) contrasts. Several examples demonstrate statistical inference for contrasts based on linkage through the pilot laboratories. Monte Carlo simulation results on performance of approximate confidence intervals are also reported.     

Statistical analysis of controlled calibration model with replicates

In this work, we generalize the controlled calibration model by assuming replication on both variables. Likelihood-based methodology is used to estimate the model parameters and the Fisher information matrix is used to construct confidence intervals for the unknown value of the regressor variable. Further, we study the local influence diagnostic method which is based on the conditional expectation of the complete-data log-likelihood function related to the EM algorithm. Some useful perturbation schemes are discussed. A simulation study is carried out to assess the effect of the measurement error on the estimation of the parameter of interest. This new approach is illustrated with a real data set.