Type II Exponentiated Half-Logistic-Topp-Leone-G Power Series Class of Distributions with Applications

This paper aims to develop a new class of distributions, namely, type II exponentiated half-logistic Topp-Leone power series (TIIEHL-TL-GPS) class of distributions. Some important properties including moments, quantiles, moment generating function, entropy and maximum likelihood estimates are derived. A simulation is conducted study to evaluate the consistency of the maximum likelihood estimates. We also present three real data examples to illustrate the usefulness of the new class of distributions. Results shows that the proposed model performs better than nested and several non-nested models on selected data sets

Time-Varying Skew in VIX Derivatives Pricing

This paper proposes a new reduced-form model for the pricing of VIX derivatives that includes an independent stochastic jump intensity factor and cojumps in the level and variance of VIX, while allowing the mean of VIX variance to be time varying. I fit the model to daily prices of futures and European options from April 2007 through December 2017. The empirical results indicate that the model significantly outperforms all other nested models and improves on benchmark by 21.6% in sample and 31.2% out of sample. The model more accurately portrays the tail behavior of VIX risk-neutral distribution for both short and long maturities, as it better captures the time-varying skew found to be largely independent of the level of the VIX smile. This paper was accepted by Kay Giesecke, finance.

Pengembangan Perangkat Pembelajaran IPA Terpadu Model Nested Berbasis Perahu Phinisi untuk Meningkatkan Keterampilan Komunikasi dan Pengetahuan Konseptual

Conventional learning models that still dominate the science learning process have a negative impact on learning psychology and student learning outcomes, for example the lecture method. In addition, the integration of local knowledge in learning almost done because the teacher thought local knowledge of science content is not relevant to modern science. This study has the prospect to develop an integrated learning tools nested models based on local wisdom phinisi boat. Products developed focuses on improving communication skills and conceptual knowledge of students. Adapting product development methods development framework Dick and Carey to modify it in 5 stages. Stages of needs analysis, product design, product development, product implementation and evaluation, and the final product. The results of product development tested in a limited class of the class VII SMPN 32 Bulukumba the 15 students who have been selected by purposive sampling. The choice of subjects represented each of 5 students with low, medium, and high abilities. Primary data were obtained from the assessment of the product by 2 experts and through the assessment questionnaire. The feasibility of the product in the category "very high". The syllabus has a validity level of 94.00%, RPP 93.75%, LKPD 96.00%, and assessment instruments 95.00%. Response practitioners and learners in the category ratings "high" and "very high" throughout the assessment indicators. In the implementation phase, learning nested models based on local wisdom boat phinisi provide more space for students to express their knowledge and digging skills

Leadership Excellence in Corporate Communications: A Multi-Group Test of Measurement Invariance

This study aims at advancing leadership research in corporate communications by introducing a more rigorous statistical approach to test whether communication professionals of different hierarchical reporting levels, years of experience, and educational backgrounds would ascribe the same meanings to the construct of leadership excellence in corporate communications via survey research. By using an established measurement model of leadership excellence in corporate communications, the study uses three samples, including senior communication executives/leaders, mid-level communication professionals, and senior college students majoring in communication and/or public relations, to conduct the measurement invariance tests. By imposing constraints to different parameters in a sequence of nested models, findings indicate that the measures of leadership excellence in corporate communications can be equivalent across multiple groups. Measurement invariance was confirmed at multiple levels, including the higher-order measurement model, configural invariance, metric invariance, scalar invariance, and error invariance. This study deepens our understanding of measurement invariance when applying multi-group comparison in testing leadership excellence. Such evidence can also be used as central principles when developing corresponding leadership training and development modules by organizations in supporting multicultural and multi-group sensitivity in leadership development. Future research and practical implications are also discussed.

“Go Wild for a While!”: A New Test for Forecast Evaluation in Nested Models

In this paper, we present a new asymptotically normal test for out-of-sample evaluation in nested models. Our approach is a simple modification of a traditional encompassing test that is commonly known as Clark and West test (CW). The key point of our strategy is to introduce an independent random variable that prevents the traditional CW test from becoming degenerate under the null hypothesis of equal predictive ability. Using the approach developed by West (1996), we show that in our test, the impact of parameter estimation uncertainty vanishes asymptotically. Using a variety of Monte Carlo simulations in iterated multi-step-ahead forecasts, we evaluated our test and CW in terms of size and power. These simulations reveal that our approach is reasonably well-sized, even at long horizons when CW may present severe size distortions. In terms of power, results were mixed but CW has an edge over our approach. Finally, we illustrate the use of our test with an empirical application in the context of the commodity currencies literature.

An Investigation of Fit Criteria within MG-CFA for Examining Non-negligible Measurement Invariance

One desirable property of a measurement process or instrument is the maximum invariance of the results across subpopulations with similar distribution of the traits. Determining measurement invariance (MI) is a statistical procedure in which different methods are used given different factors, such as the nature of the data (e.g. continuous, or discrete, completeness), sample size, measurement framework (e.g. observed scores, latent variable modeling), and other context-specific factors. To evaluate the statistical results, numerical criteria are often used, derived from theory, simulation, or practice. One statistical method to evaluate MI is multiple-group confirmatory factor analysis (MG-CFA) in which the amount of change in fit indices of nested models, such as comparative fit index (CFI), Tucker-Lewis fit index (TLI), and the root mean squared error of approximation (RMSEA), are used to determine if the lack of invariance is non-trivial. Currently, in the MG-CFA framework for establishing MI, the recommended effect size is a change of less than 0.01 in CFI/TLI measures (Cheung & Rensvold, 2002). However, the recommended cutoff value is a very general index and may not be appropriate under some conditions, such as dichotomous indicators, different estimation methods, different sample sizes, and model complexity. In addition, in determining the cutoff value, consequences to the lack of invariance have been ignored in the current research. To address these gaps, the present research undertakes to evaluate the appropriateness of the current effect size of CFI or TLI < 0.01 in educational measurement settings, where the items are dichotomous, the item response functions follow an item response theory (IRT) model, estimation method is robust weighted least squares, and the focal and reference groups differ from each other on the IRT scale by 0.5 units (equivalent to ±1 raw score). A simulation study was performed with five (crossed) factors: percent of differential functioning items, IRT model, IRT a and b parameters, and the sample size. The results of the simulation study showed that the cutoff value of a CFI/TLI < 0.01 for establishing MI is not appropriate for educational settings under the foregoing conditions.

The Truncated Burr X-G Family of Distributions: Properties and Applications to Actuarial and Financial Data

In this article, the “truncated-composed” scheme was applied to the Burr X distribution to motivate a new family of univariate continuous-type distributions, called the truncated Burr X generated family. It is mathematically simple and provides more modeling freedom for any parental distribution. Additional functionality is conferred on the probability density and hazard rate functions, improving their peak, asymmetry, tail, and flatness levels. These characteristics are represented analytically and graphically with three special distributions of the family derived from the exponential, Rayleigh, and Lindley distributions. Subsequently, we conducted asymptotic, first-order stochastic dominance, series expansion, Tsallis entropy, and moment studies. Useful risk measures were also investigated. The remainder of the study was devoted to the statistical use of the associated models. In particular, we developed an adapted maximum likelihood methodology aiming to efficiently estimate the model parameters. The special distribution extending the exponential distribution was applied as a statistical model to fit two sets of actuarial and financial data. It performed better than a wide variety of selected competing non-nested models. Numerical applications for risk measures are also given.

A nested model for tuberculosis: Combining within-host and between-host processes in a single framework

Tuberculosis (TB) is among the 10 top causes of deaths worldwide, and one-quarter of the world population hosts latent TB pathogens. Therefore, avoiding the emergence of drug-resistant strains has become a central issue in TB control. In this work, we propose a nested model for TB transmission and control, wherein both within-host and between-host dynamics are modeled. We use the model to compare the effects of three types of antibiotic treatment protocols and combinations thereof in an in silico population. For a fixed value of antibiotics clearance rate and relative efficacy against resistant strains, the oscillating intermittent protocol, pure or combined, is the most effective against the sensitive strains. However, this protocol also creates a selective advantage for the resistant strains, returning the worst result in comparison to the other protocols. We suggest that nested models should be further developed, since they might be able to inform decision-makers regarding the optimal TB control protocols to be applied under the specific parameters and other epidemiological factors in different populations.

An Alternative Promotion Time Cure Model with Overdispersed Number of Competing Causes: An Application to Melanoma Data

A cure rate model under the competing risks setup is proposed. For the number of competing causes related to the occurrence of the event of interest, we posit the one-parameter Bell distribution, which accommodates overdispersed counts. The model is parameterized in the cure rate, which is linked to covariates. Parameter estimation is based on the maximum likelihood method. Estimates are computed via the EM algorithm. In order to compare different models, a selection criterion for non-nested models is implemented. Results from simulation studies indicate that the estimation method and the model selection criterion have a good performance. A dataset on melanoma is analyzed using the proposed model as well as some models from the literature.