ON THE ESTIMATION OF TOTAL WEIGHT IN CHEMICAL BALANCE WEXGHING DESIGNS1

This paper is concerned with the problem of estimation of total weight in a chemical balance weighing design. Some results regarding the estimability of the total weight are obtained and a lower bound for the variance of the estimated total weight is given. Finally, a series of weighing designs estimating the total weight in an ‘optimum’ manner is reported.     

Exponentiated Chen distribution: Properties and estimation

This article addresses various properties and estimation methods for the Exponentiated Chen distribution. Although, our main focus is on estimation from frequentist point of view, yet, some statistical and reliability characteristics for the model are derived. We briefly describe different estimation procedures, namely, the method of maximum likelihood estimation, percentile estimation, least square and weighted least-square estimation, maximum product of spacings estimation, Cramér-von-Mises estimation, Anderson–Darling, and right-tail Anderson–Darling estimation. Monte Carlo simulations are performed to compare the performances of the proposed methods of estimation for both small and large samples. Finally, the potentiality of the model is analyzed by means of three real datasets.     

Extended exponential distribution based on order statistics

The extended exponential distribution due to Nadarajah and Haghighi (2011 Nadarajah, S., Haghighi, F. (2011). An extension of the exponential distribution. Statistics 45:543–558.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) is an alternative to and always provides better fits than the gamma, Weibull, and the exponentiated exponential distributions whenever the data contain zero values. We establish recurrence relations for the single and product moments of order statistics from the extended exponential distribution. These recurrence relations enable computation of the means, variances, and covariances of all order statistics for all sample sizes in a simple and efficient manner. By using these relations, we tabulate the means, variances, and covariances of order statistics and derive best linear unbiased estimates of the extended exponential distribution. Finally, a data application is provided.     

Carbon budgeting in golf course soils of Central Ohio

As global climate change (GCC) becomes an increasing societal concern, scientists are assessing soils’ capacity to sequester atmospheric CO₂ to off-set anthropogenic emissions. Therefore, this study was conducted to determine C sequestration potential in golf turfgrass systems in Central Ohio, USA, and to determine the effect of management practices on the net soil C sink capacity. Ohio farmland soils converted to golf course turfgrasses sequestered C at mean rates of 3.55 ± 0.08 Mg/ha/yr in fairways and 2.64 ± 0.06 Mg/ha/yr in rough areas. Soils in both fairway and rough areas sequestered C to 15 cm depth. However, hidden C costs of golf course development and management were also significant and major C emissions were attributed to diesel fuel combustion (6,557 kg Ce(Carbon Equivalents)/yr), unleaded fuel combustion (3,618 kg Ce/yr), N fertilizer use (1,498 kg Ce/yr), fungicide application (1,377 kg Ce/yr) and irrigation (626 kg Ce/yr), for an overall C emission of 14.15 Mg Ce per course per year (0.30 Mg C/ha/yr). Analysis of sequestration and emissions data showed that a newly constructed golf course has a technical C sequestration capacity of 2,224 Mg C over a 91.4 year period or the equivalent of 0.44 Mg C/ha/yr. However, the large C emissions generated by maintenance practices render courses from sinks to sources within 30 years. To maximize the potential environmental benefits of turfgrass systems while increasing the economic efficiency of each site, management practices with low C-intensity should be utilized.     

Multiparameter estimation in truncated power series distributions under the stein's loss

LetX ₁,…,X _p be p(≥2)independent random variables, where each X.has a distribution belonging to a one parameter truncated power series

distribution. The problem is to estimate simultaneously the unknown parameters under asymmetric loss developed by James and Stein (Proc. Fourth Berkeley Symp. Math. Statist. Prob. 1, 361-380). Several new classes of dominating estimators are obtained by solving a certain difference inequality.     

Bayesian analysis of multivariate mortality data with large families

This paper presents a Bayesian method for the analysis of toxicological multivariate mortality data when the discrete mortality rate for each family of subjects at a given time depends on familial random effects and the toxicity level experienced by the family. Our aim is to model and analyse one set of such multivariate mortality data with large family sizes: the potassium thiocyanate (KSCN) tainted fish tank data of O'Hara Hines. The model used is based on a discretized hazard with additional time-varying familial random effects. A similar previous study (using sodium thiocyanate (NaSCN)) is used to construct a prior for the parameters in the current study. A simulation-based approach is used to compute posterior estimates of the model parameters and mortality rates and several other quantities of interest. Recent tools in Bayesian model diagnostics and variable subset selection have been incorporated to verify important modelling assumptions regarding the effects of time and heterogeneity among the families on the mortality rate. Further, Bayesian methods using predictive distributions are used for comparing several plausible models.     

On resolvable PBIB designs

Resolvable solutions for some two associate PBIB designs obtained by duplicating some non-resolvable designs are given. For the same designs 2-, 3- and 5-resolvable solutions are reported by Clatworthy (1973). A method of construction and some new resolvable PBIB designs obtained through this are given.     

COMPUTER AIDED-CONSTRUCTION OF D-OPTIMAL 2m FRACTIONAL DESIGNS OF RESOLUTION V

A new exchange algorithm for construction of 2^mD-optimal fractional factorial design (FFD) is devised. This exchange algorithm is a modification of the one due to Fedorov (1969, 1972) and is an improvement over similar algorithm due to Mitchell (1974) and Galil & Kiefer (1980). This exchange algorithm is then used to construct 54 D-optimal 2^m-FFD's of resolution V for m = 4,5,6.     

A note on incomplete block designs for symmetrical parallel line assays

Incomplete block designs estimating the relative potency free from block effects have been discussed. A method of constructing a series of such designs has been presented.