Issues

Journal & Issues

Volume 59 (2022): Issue 1 (June 2022)

Volume 58 (2021): Issue 2 (December 2021)

Volume 58 (2021): Issue 1 (June 2021)

Volume 57 (2020): Issue 2 (December 2020)

Volume 57 (2020): Issue 1 (June 2020)

Volume 56 (2019): Issue 2 (December 2019)

Volume 56 (2019): Issue 1 (June 2019)

Volume 55 (2018): Issue 2 (December 2018)

Volume 55 (2018): Issue 1 (June 2018)

Volume 54 (2017): Issue 2 (December 2017)

Volume 54 (2017): Issue 1 (June 2017)

Volume 53 (2016): Issue 2 (December 2016)

Volume 53 (2016): Issue 1 (June 2016)

Volume 52 (2015): Issue 2 (December 2015)

Volume 52 (2015): Issue 1 (June 2015)

Volume 51 (2014): Issue 2 (December 2014)

Volume 51 (2014): Issue 1 (June 2014)

Volume 50 (2013): Issue 2 (December 2013)

Volume 50 (2013): Issue 1 (June 2013)

Volume 49 (2012): Issue 2 (December 2012)

Volume 49 (2012): Issue 1 (June 2012)

Journal Details
Format
Journal
eISSN
2199-577X
First Published
17 Aug 2013
Publication timeframe
2 times per year
Languages
English

Search

Volume 59 (2022): Issue 1 (June 2022)

Journal Details
Format
Journal
eISSN
2199-577X
First Published
17 Aug 2013
Publication timeframe
2 times per year
Languages
English

Search

6 Articles
access type Open Access

Relative exponential sum-symmetry model and orthogonal decomposition of the sum-symmetry model for ordinal square contingency tables

Published Online: 30 Jun 2022
Page range: 1 - 10

Abstract

Summary

This study proposes a new exponential sum-symmetry model for square contingency tables with same row and column ordinal classifications. In the existing exponential sum-symmetry (ESS) model, the probability that the sum of row and column levels is t, where the row level is less than the column level, is ∆t−2 times higher than the probability that the sum of row and column levels is t, where the row level is greater than the column level. On the other hand, in the proposed ESS model, the ratio of these two probabilities is ∆t/3. In other words, in the existing ESS model, the ratio of the two probabilities varies exponentially depending on the absolute gap between t and 2, while in the proposed ESS model, the ratio of the two probabilities varies exponentially depending on the relative gap between t and 3, although in both ESS models, the ratio of the two probabilities is ∆ when t is the minimum value (i.e., t = 3). Moreover, this study introduces a new decomposition theorem for the sum-symmetry model using the proposed ESS. The proposed decomposition theorem satisfies asymptotic equivalence for the test statistic.

Keywords

  • absolute gap
  • asymmetry
  • asymptotic equivalence
  • relative gap
  • symmetry
  • test statistic
access type Open Access

Environmental impact on downy mildew infection for different pea varieties

Published Online: 30 Jun 2022
Page range: 11 - 22

Abstract

Summary

In general, varieties of any cultivated species can differ in many aspects. One of the desirable traits in breeding new varieties is high yield, which can be significantly reduced by plant diseases. This study is an extension of previous research about the resistance of seed pea lines to downy mildew, and provides an extended analysis of this type of experiment. The probability of a degree of infection is determined based on a logistic model with a multinomial distribution. In the analysis the impact of a fixed effect of variety and random environmental effects is considered. It is shown that the environmental effects (combinations of years and location – macro-environments) significantly influence the resistance to diseases, and the differences among environments are larger than the variability of differences among genotypes over all environments. For two types of soils (light and rich) the most resistant varieties, which are significantly different from the control variety, are indicated.

Keywords

  • multi-environment trials
  • resistance of variety
  • infection
  • goodness of fit
  • logistic models
access type Open Access

Maximum Likelihood and L2 Environmental Indices in Joint Regression Analysis

Published Online: 30 Jun 2022
Page range: 23 - 46

Abstract

Summary

This paper describes an iterative analysis of incomplete genotype × environment data. L2 environmental indices were introduced to enable the use of Joint Regression Analysis (JRA) in analyzing experiments with incomplete blocks. We now show how, once normality of yields is assumed, the introduction of L2 environmental indices provides a theoretical framework for Joint Regression Analysis. Using this framework, maximum likelihood estimators are obtained and likelihood ratio tests are derived. It is noted that the technique allows unequal weighting of data, and the special case of complete blocks is discussed.

Keywords

  • Joint Regression Analysis
  • maximum likelihood estimators
  • likelihood ratio tests
  • L environmental indices
access type Open Access

Contribution to spring balance weighing designs

Published Online: 30 Jun 2022
Page range: 47 - 53

Abstract

Summary

In this paper, we present some new results regarding spring balance weighing designs. We consider issues with regard to conditions for the existence of optimal designs, and give examples of optimal designs.

Keywords

  • plan of experiment
  • spring balance weighing design
access type Open Access

On a construction procedure for split-block-plot designs based on the Khatri–Rao product of incidence matrices

Published Online: 30 Jun 2022
Page range: 55 - 63

Abstract

Summary

The construction of incomplete split-block-plot (SBP) designs for three-factor experiments is investigated. A semi-Kronecker (Khatri–Rao) product of matrices is used in the construction procedure. With this method some generated designs are obtained where column treatments and subplot treatments are allocated in balanced square lattice designs, while row treatments are in a randomized complete block design. Experiments with an orthogonal block structure are considered. In this paper we consider designs which are generally balanced. This allows us to give the stratum efficiency factors for treatment combination contrasts in the proposed split-block-plot designs.

Keywords

  • Generally balanced designs
  • Semi-Kronecker product of matrices
  • Square lattice designs
  • Split-block-plot designs
  • Stratum efficiency factors
access type Open Access

Considering distance measures in Statistics

Published Online: 30 Jun 2022
Page range: 65 - 75

Abstract

Summary

The target of this paper is to offer a compact review of the so called distance methods in Statistics, which cover all the known estimation methods. Based on this fact we propose a new step, to adopt from Information Theory, the divergence measures, as distance methods, to compare two distributions, and not only to investigate if the means or the variances of the distributions are equal. Some useful results towards this line of thought are presented, adopting a compact form for all known divergence measures, and are appropriately analyzed for Biometrical, and not only, applications.

Keywords

  • Euclidean distance
  • information theory
  • bioassays
6 Articles
access type Open Access

Relative exponential sum-symmetry model and orthogonal decomposition of the sum-symmetry model for ordinal square contingency tables

Published Online: 30 Jun 2022
Page range: 1 - 10

Abstract

Summary

This study proposes a new exponential sum-symmetry model for square contingency tables with same row and column ordinal classifications. In the existing exponential sum-symmetry (ESS) model, the probability that the sum of row and column levels is t, where the row level is less than the column level, is ∆t−2 times higher than the probability that the sum of row and column levels is t, where the row level is greater than the column level. On the other hand, in the proposed ESS model, the ratio of these two probabilities is ∆t/3. In other words, in the existing ESS model, the ratio of the two probabilities varies exponentially depending on the absolute gap between t and 2, while in the proposed ESS model, the ratio of the two probabilities varies exponentially depending on the relative gap between t and 3, although in both ESS models, the ratio of the two probabilities is ∆ when t is the minimum value (i.e., t = 3). Moreover, this study introduces a new decomposition theorem for the sum-symmetry model using the proposed ESS. The proposed decomposition theorem satisfies asymptotic equivalence for the test statistic.

Keywords

  • absolute gap
  • asymmetry
  • asymptotic equivalence
  • relative gap
  • symmetry
  • test statistic
access type Open Access

Environmental impact on downy mildew infection for different pea varieties

Published Online: 30 Jun 2022
Page range: 11 - 22

Abstract

Summary

In general, varieties of any cultivated species can differ in many aspects. One of the desirable traits in breeding new varieties is high yield, which can be significantly reduced by plant diseases. This study is an extension of previous research about the resistance of seed pea lines to downy mildew, and provides an extended analysis of this type of experiment. The probability of a degree of infection is determined based on a logistic model with a multinomial distribution. In the analysis the impact of a fixed effect of variety and random environmental effects is considered. It is shown that the environmental effects (combinations of years and location – macro-environments) significantly influence the resistance to diseases, and the differences among environments are larger than the variability of differences among genotypes over all environments. For two types of soils (light and rich) the most resistant varieties, which are significantly different from the control variety, are indicated.

Keywords

  • multi-environment trials
  • resistance of variety
  • infection
  • goodness of fit
  • logistic models
access type Open Access

Maximum Likelihood and L2 Environmental Indices in Joint Regression Analysis

Published Online: 30 Jun 2022
Page range: 23 - 46

Abstract

Summary

This paper describes an iterative analysis of incomplete genotype × environment data. L2 environmental indices were introduced to enable the use of Joint Regression Analysis (JRA) in analyzing experiments with incomplete blocks. We now show how, once normality of yields is assumed, the introduction of L2 environmental indices provides a theoretical framework for Joint Regression Analysis. Using this framework, maximum likelihood estimators are obtained and likelihood ratio tests are derived. It is noted that the technique allows unequal weighting of data, and the special case of complete blocks is discussed.

Keywords

  • Joint Regression Analysis
  • maximum likelihood estimators
  • likelihood ratio tests
  • L environmental indices
access type Open Access

Contribution to spring balance weighing designs

Published Online: 30 Jun 2022
Page range: 47 - 53

Abstract

Summary

In this paper, we present some new results regarding spring balance weighing designs. We consider issues with regard to conditions for the existence of optimal designs, and give examples of optimal designs.

Keywords

  • plan of experiment
  • spring balance weighing design
access type Open Access

On a construction procedure for split-block-plot designs based on the Khatri–Rao product of incidence matrices

Published Online: 30 Jun 2022
Page range: 55 - 63

Abstract

Summary

The construction of incomplete split-block-plot (SBP) designs for three-factor experiments is investigated. A semi-Kronecker (Khatri–Rao) product of matrices is used in the construction procedure. With this method some generated designs are obtained where column treatments and subplot treatments are allocated in balanced square lattice designs, while row treatments are in a randomized complete block design. Experiments with an orthogonal block structure are considered. In this paper we consider designs which are generally balanced. This allows us to give the stratum efficiency factors for treatment combination contrasts in the proposed split-block-plot designs.

Keywords

  • Generally balanced designs
  • Semi-Kronecker product of matrices
  • Square lattice designs
  • Split-block-plot designs
  • Stratum efficiency factors
access type Open Access

Considering distance measures in Statistics

Published Online: 30 Jun 2022
Page range: 65 - 75

Abstract

Summary

The target of this paper is to offer a compact review of the so called distance methods in Statistics, which cover all the known estimation methods. Based on this fact we propose a new step, to adopt from Information Theory, the divergence measures, as distance methods, to compare two distributions, and not only to investigate if the means or the variances of the distributions are equal. Some useful results towards this line of thought are presented, adopting a compact form for all known divergence measures, and are appropriately analyzed for Biometrical, and not only, applications.

Keywords

  • Euclidean distance
  • information theory
  • bioassays

Plan your remote conference with Sciendo