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Sangita Das

Publications and source records attributed to Sangita Das.

11 recordsLinked to original sources

Ordering results for extreme claim amounts based on random number of claims

Consider two sequences of heterogeneous and independent portfolios of risks $T_1,T_2,\ldots$ and $T^*_{1}, T^*_{2},\ldots$ and, let $N_1$ and $N_2$ be two positive integer-valued random variables, independent of $T_i'$ and $T^*_i$, respectively. In this article, we investigate different stochastic inequalities involving $\min\{T_1,\ldots,T_{N_1}\}$ and $\min\{T^*_1,\ldots,T^*_{N_2}\},$ and $\max\{T_1,\ldots,T_{N_1}\}$ and $\max\{T^*_1,\ldots,T^*_{N_2}\}$ in the sense of usual stochastic order and reversed hazard rate order concerning maltivariate chain majorization order. These new results strengthen and generalize some of the well known results in the literature, including \cite{barmalzan2017ordering}, \cite{balakrishnan2018} and \cite{kundu2021_shock} for the case of random claim sizes. Different numerical examples are provided to highlight the applicability of this work. Finally, some interesting applications of our results in reliability theory and auction theory are presented.

q-fin.RM

Ordering results for random maxima and minima from two dependent Kumaraswamy generalized distributed samples

Let $\{X_{1},\ldots,X_{N_1}\}$ and $\{Y_{1},\ldots,Y_{N_2}\}$ be two sequences of interdependent heterogeneous samples, where for $i=1,\ldots,N_{1},$ $X_{i}\sim \text{Kw-G}(x, α_{i}, γ_{i};G)$ and for $i=1,\ldots,N_{2},$ $Y_{i}\sim \text{Kw-G}(x, β_{i}, δ_{i};H),$ where $G$ and $H$ are baseline distributions in the Kumaraswamy generalized model and $N_1$ and $N_2$ are two positive integer-valued random variables, independently of $X_{i}'$s and $Y_{i}'$s, respectively. In this article, we establish several stochastic orders such as usual stochastic, hazard rate, reversed hazard rate, dispersive and likelihood ratio orders between the random maxima ($X_{{N_1}:{N_1}}$ and $Y_{{N_2}:{N_2}}$) and the random minima ($X_{{1}:{N_1}}$ and $X_{{1}:{N_2}}$), when the sample sizes are different and random (positive).

math.ST

Ordering results between two finite arithmetic mixture models with multiple-outlier location-scale distributed components

In this article, we introduce finite mixture models (FMMs) renowned for capturing population heterogeneity. Our focus lies in establishing stochastic comparisons between two arithmetic (finite) mixture models, employing the vector majorization concept in the context of various univariate orders of magnitude, transform, and variability. These comparisons are conducted within the framework of multiple-outlier location-scale models. Specifically, we derive sufficient conditions for comparing two finite arithmetic mixture models with components distributed in a multiple-outlier location-scale model.

math.ST

Child labour and schooling decision of the marginal farmer households: An empirical evidence from the East Medinipur district of West Bengal, India

Based on the field investigation of West Bengal, this paper investigates whether the school-aged children of the marginal farmer households are full-time paid labourers or unpaid domestic labourers along with schooling or regular students. Probit Regression analysis is applied here to assess the influencing factors for reducing the size of the child labour force in practice. The result shows that the higher is the earning of the adult members of the households, the lower is the incidence of child labour. Moreover, the credit accessibility of the mother from the Self-help group and more person-days of the father in work in a reference year are also responsible for reducing the possibility of a child turning into labour. The study further suggests that the younger age of the father, education of fathers, and low operational landholdings are positive and significant determinants to decide on a child education by restricting their excessive domestic work burden.

econ.GN

Inequality in Educational Attainment: Urban-Rural Comparison in the Indian Context

The article tries to compare urban and rural literacy of fifteen selected Indian states during 1981 - 2011 and explores the instruments which can reduce the disparity in urban and rural educational attainment. The study constructs the Sopher urban-rural differential literacy index to analyze the trends of literacy disparity across fifteen states in India over time. Although literacy disparity has decreased over time, Sopher index shows that the states of Andhra Pradesh, Madhya Pradesh, Gujarat, Odisha, Maharashtra and even Karnataka faced high inequality in education between urban and rural India in 2011. Additionally, the Fixed Effect panel data regression technique has been applied in the study to identify the factors which influence urban-rural inequality in education. The model shows that the following factors can reduce literacy disparity between urban and rural areas of India: low fertility rate in rural women, higher percentages of rural females marrying after the age of 21 years, educational attainment of mothers and their labour force participation rate in rural areas.

econ.GN

Impact of Comprehensive Data Preprocessing on Predictive Modelling of COVID-19 Mortality

Accurate predictive models are crucial for analysing COVID-19 mortality trends. This study evaluates the impact of a custom data preprocessing pipeline on ten machine learning models predicting COVID-19 mortality using data from Our World in Data (OWID). Our pipeline differs from a standard preprocessing pipeline through four key steps. Firstly, it transforms weekly reported totals into daily updates, correcting reporting biases and providing more accurate estimates. Secondly, it uses localised outlier detection and processing to preserve data variance and enhance accuracy. Thirdly, it utilises computational dependencies among columns to ensure data consistency. Finally, it incorporates an iterative feature selection process to optimise the feature set and improve model performance. Results show a significant improvement with the custom pipeline: the MLP Regressor achieved a test RMSE of 66.556 and a test R-squared of 0.991, surpassing the DecisionTree Regressor from the standard pipeline, which had a test RMSE of 222.858 and a test R-squared of 0.817. These findings highlight the importance of tailored preprocessing techniques in enhancing predictive modelling accuracy for COVID-19 mortality. Although specific to this study, these methodologies offer valuable insights into diverse datasets and domains, improving predictive performance across various contexts.

cs.LG

Orderings of extremes among dependent extended Weibull random variables

In this work, we consider two sets of dependent variables $\{X_{1},\ldots,X_{n}\}$ and $\{Y_{1},\ldots,Y_{n}\}$, where $X_{i}\sim EW(α_{i},λ_{i},k_{i})$ and $Y_{i}\sim EW(β_{i},μ_{i},l_{i})$, for $i=1,\ldots, n$, which are coupled by Archimedean copulas having different generators. Also, let $N_{1}$ and $N_{2}$ be two non-negative integer-valued random variables, independent of $X_{i}'$s and $Y_{i}'$s, respectively. We then establish different inequalities between two extremes, namely, $X_{1:n}$ and $Y_{1:n}$ and $X_{n:n}$ and $Y_{n:n}$, in terms of the usual stochastic, star, Lorenz, hazard rate, reversed hazard rate and dispersive orders. We also establish some ordering results between $X_{1:{N_{1}}}$ and $Y_{1:{N_{2}}}$ and $X_{N_{1}:{N_{1}}}$ and $Y_{N_{2}:{N_{2}}}$ in terms of the usual stochastic order. Several examples and counterexamples are presented for illustrating all the results established here. Some of the results here extend the existing results of Barmalzan et al. (2020).

stat.OT

On comparison of the second-order statistics from independent and interdependent exponentiated location-scale distributed random variables

Consider two batches of independent or interdependent exponentiated location-scale distributed heterogeneous random variables. This article investigates ordering results for the second-order statistics from these batches when a vector of parameters is switched to another vector of parameters in the specified model. Sufficient conditions for the usual stochastic order and the hazard rate order are derived. Some applications of the established results are presented.

math.ST

Ordering results between the largest claims arising from two general heterogeneous portfolios

This work is entirely devoted to compare the largest claims from two heterogeneous portfolios. It is assumed that the claim amounts in an insurance portfolio are nonnegative absolutely continuous random variables and belong to a general family of distributions. The largest claims have been compared based on various stochastic orderings. The established sufficient conditions are associated with the matrices and vectors of model parameters. Applications of the results are provided for the purpose of illustration.

q-fin.RM

Some new ordering results on stochastic comparisons of second largest order statistics from independent and interdependent heterogeneous distributions

The second-largest order statistic is of special importance in reliability theory since it represents the time to failure of a $2$-out-of-$n$ system. Consider two $2$-out-of-$n$ systems with heterogeneous random lifetimes. The lifetimes are assumed to follow heterogeneous general exponentiated location-scale models. In this communication, the usual stochastic and reversed hazard rate orders between the systems' lifetimes are established under two cases. For the case of independent random lifetimes, the usual stochastic order and the reversed hazard rate order between the second-largest order statistics are obtained by using the concept of vector majorization and related orders. For the dependent case, the conditions under which the usual stochastic order between the second-largest order statistics holds are investigated. To illustrate the theoretical findings, some special cases of the exponentiated location-scale model are considered.

math.ST

Ordering results of extreme order statistics from multiple-outlier scale models with dependence

In this paper, we focus on stochastic comparisons of extreme order statistics stemming from multiple-outlier scale models with dependence. Archimedean copula is used to model dependence structure among nonnegative random variables. Sufficient conditions are obtained for comparison of the largest order statistics in the sense of the usual stochastic, reversed hazard rate, star and Lorenz orders. The smallest order statistics are also compared with respect to the usual stochastic, hazard rate, star and Lorenz orders. To illustrate the theoretical establishments, some examples are provided.

math.ST