摘要:

SummaryThere has been much work on the use of neighbouring plots to control environmental variation in the analysis of agricultural field experiments. In particular, the Residual Maximum Likelihood Neighbour (REMLN) analysis of Gleeson&Cullis (1987) appears very promising. The application of the REMLN analysis to an unequally replicated field trial augmented with an additional variety planted every six plots in a grid system is here compared with a covariance (COV) analysis using the neighbouring grid or check plot values as the covariate. The results indicate that the REMLN analysis gives more accurate estimates of treatment contrasts than the COV analyses, but that the estimate of treatment means can be biased. The bias depends on the mean of the check plot. This bias can be removed by adjusting the estimates of the treatment means such that their average equals the average of the raw means rather than that of the raw data.

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01037.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryIncipient sexual isolation between two strains ofD. metanogasterwas tested by male choice experiments. During ten years (150 generations) one strain, named Se, was reared in a food medium containing 10‐‐4M sodium selenite, while the other, named Co, was kept under normal conditions. Both strains were derived from the same natural population. There was no evidence of preference for a mate of the same strain. There was an interaction between type of female and duration of time available for mating. Se males inseminated fewer females and fewer Se females were inseminated over

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01038.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryUsing a global window width kernel estimator to estimate an approximately symmetric probability density with high kurtosis usually leads to poor estimation because good estimation of the peak of the distribution leads to unsatisfactory estimation of the tails and vice versa. The technique proposed corrects for kurtosis via a transformation of the data before using a global window width kernel estimator. The transformation depends on a “generalised smoothing parameter” consisting of two real‐valued parameters and a window width parameter which can be selected either by a simple graphical method or, for a completely data‐driven implementation, by minimising an estimate of mean integrated squared error. Examples of real and simulated data demonstrate the effectiveness of this approach, which appears suitable for a wide range of symmetric, unimodal densities. Its performance is similar to ordinary kernel estimation in situations where the latter is effective, e.g. Gaussian densities. For densities like the Cauchy where ordinary kernel estimation is not satisfactory, our methodology offers a substantial impr

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01039.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThis paper considers the problem of estimating a cumulative distribution function (cdf), when it is known a priori to dominate a known cdf. The estimator considered is obtained by adjusting the empirical cdf using the prior information. This adjusted estimator is shown to be consistent, its limiting distribution is found, and its mean squared error (MSE) is shown to be smaller than the MSE of the empirical cdf. Its asymptotic efficiency (compared to the empirical cdf) is also found.

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01040.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryFor estimating the common mean of a bivariate normal distribution, Krishnamoorthy&Rohatgi (1989) proposed some estimators which dominate the maximum likelihood estimator in a large region of the parameter space. We consider some modifications of these estimators and study their risk performance.

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01041.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryWe consider the problem of uniformly minimum variance unbiased (UMVU) estimation of U‐estimable functions of three unknown truncation parameters based on two independent random samples: one from a two‐truncation parameter family and the other from a one‐truncation parameter family. In particular, we obtain the UMVU estimator of the functional Pr{Y>X} and the shortest confidence intervals for some parametric func

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01042.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryWe show that, within the family of power transformations of a Chisquare variable, the square and fourth roots minimize Pearson's index of kurtosis. Two new transtormations of the fourth root, a symmetrized‐truncated version and its linear combination with the square root are also studied. The first transformation shows a considerable improvement over the fourth root while the second one turns out to be even more accurate than Hilferty‐Wilson's cube root transformat

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01043.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryFor two‐parameter exponential populations with the same scale parameter (known or unknown) comparisons are made between the location parameters. This is done by constructing confidence intervals, which can then be used for selection procedures. Comparisons are made with a control, and with the (unknown) “best” or “worst” population. Emphasis is laid on finding approximations to the confidence so that calculations are simple and tables are not necessary. (Since we consider unequal sample sizes, tables for exact values would need to be e

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01044.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryMeasurements taken on a continuous process (e.g. production of chemicals, ore processing, steel production) often exhibit autocorrelation. Such correlation between successive measurements can be avoided only by taking measurements at widely separated times, but this delays the results. We discuss the impact of this correlation on experimental designs which for a continuous process must include the sequence in which treatment combinations are applied and the spacing between samples. The variogram of the process is a convenient Summary of the correlation. Formulae for the variance of the mean of measurements taken on a continuous process and of contrasts calculated from such measurements are simple expressions in terms of the variogram. These formulae allow a simple approach to experimental designs that avoid unnecessary delays.

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01045.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThis paper examines the effect of randomisation restrictions, either to satisfy conditions for a balanced incomplete block design or to attain a higher level of partial neighbour balance, on the average variance of pair‐wise treatment contrasts under a neighbour model discussed by Gleeson&Cullis (1987). Results suggest that smaller average pairwise variances can be obtained by ignoring requirements for incomplete block designs and concentrating on achieving a higher level of partial neighbour balance. Field layout of the design, although often determined by practical constraints, e.g. size, shape of site, minimum plot size and experimental husbandry, may markedly affect average pairwise variance. For the one‐dimensional (row‐wise) neighbour model considered here, investigation of three different layouts suggests that for a rectangular array of plots, smaller average pairwise variances can generally be obtained from layouts with fewer rows and more plots pe

ISSN:0004-9581    

DOI:10.1111/j.1467-842X.1992.tb01046.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY