Search results for "Regression"

Smoothed score confidence interval for the breakpoint in segmented regression

2012

For the breakpoint parameter in segmented regression we consider confidence intervals based on the score statistic. Due to unsmoothness of the score, we propose to build the confidence intervals using its smoothed version under proper shape restrictions. Some simulations are presented to assess the finite sample performance of the proposed approach.

Testing for a breakpoint in segmented regression: a pseudo score approach

2011

To overcome the well known oddities in testing for the existence of a breakpoint in segmented regression models, we discuss a novel approach based on the Pearson X2 statistic which can be understood as an approximation of the Score statistic. We describe the method and present results from some simulations.

Wiener-Granger Causality in Network Physiology with Applications to Cardiovascular Control and Neuroscience

2016

Since the operative definition given by C. W. J. Granger of an idea expressed by N. Wiener, the Wiener–Granger causality (WGC) has been one of the most relevant concepts exploited by modern time series analysis. Indeed, in networks formed by multiple components, working according to the notion of segregation and interacting with each other according to the principle of integration, inferring causality has opened a window on the effective connectivity of the network and has linked experimental evidences to functions and mechanisms. This tutorial reviews predictability improvement, information-based and frequency domain methods for inferring WGC among physiological processes from multivariate…

Prenatal air pollution exposure and growth and cardio-metabolic risk in preschoolers

2020

Objectives: We investigated the association between outdoor air pollutants exposure in the first trimester of pregnancy, and growth and cardio-metabolic risk at four years of age, and evaluated the mediating role of birth weight. Methods: We included mother-child pairs (N = 1,724) from the Spanish INMA birth cohort established in 2003-2008. First trimester of pregnancy nitrogen dioxide (NO2) and fine particles (PM2.5) exposure levels were estimated. Height, weight, waist circumference, blood pressure, and lipids were measured at four years of age. Body mass index (BMI) trajectories from birth to four years were identified. Results: Increased PM2.5 exposure in the first trimester of pregnanc…

Customer Value Framework and Recommendation Intention: The Moderating Role of Customer Characteristics in an Online Travel Community

2019

The aim of this study was to develop and test a model that examined the interactions among the customer value framework, recommendation intention and customer characteristics in an online travel community (OTC). Data were obtained using Amazon Mechanical Turk from 251 members of an OTC as a sample. The partial least squares method was used to analyse the data. We found that all the variables of the customer value framework, including functional value, hedonic value and social value, were positively related to recommendation intention. In addition, using multi-group analyses, the study found differences between how different customer segments perceive each of the value dimensions and their e…

Differential effects of perceptions of equal, favourable and unfavourable autonomy support on educational and well-being outcomes

2019

Abstract In this study, we examined whether high-school students experienced optimal educational and well-being outcomes when they perceived that they and their classmates received an equal, rather than unequal, and high amount of autonomy support from teachers. In a prospective study that aimed to predict academic grades and well-being outcomes, surface analyses of polynomial regression equations pointed that perceptions of equal autonomy support were the most optimal in terms of yielding highest levels of need satisfaction, autonomous forms of motivation and happiness with math courses. Additionally, in accordance with tenets of self-determination theory, we demonstrated that effects asso…

Optimal Spectral Wavelengths for Discriminating Orchard Species Using Multivariate Statistical Techniques

2019

Sustainable management of orchard fields requires detailed information about the tree types, which is a main component of precision agriculture programs. To this end, hyperspectral imagery can play a major role in orchard tree species mapping. Efficient use of hyperspectral data in combination with field measurements requires the development of optimized band selection strategies to separate tree species. In this study, field spectroscopy (350 to 2500 nm) was performed through scanning 165 spectral leaf samples of dominant orchard tree species (almond, walnut, and grape) in Chaharmahal va Bakhtiyari province, Iran. Two multivariable methods were employed to identify the optimum wavelengths:…

Organizational innovation for SME'S: a model for Latvia

2020

Small and medium-sized enterprises (SMEs) can be a significant source of innovation in small economies. SMEs face challenges of limited capacity, personnel and resources for long-term investments. Additionally, they might not see and understand the benefits of innovation. Implementation of organizational innovation (OI) could give such enterprises an opportunity to improve competitiveness and develop other types of innovation. The purpose of this study is to develop a model, explaining OI through such factors as organizational culture (OC) and knowledge management (KM) in SMEs via an empirical study across various industries. Surveying 600 SMEs in Latvia, the authors explore the contributio…

Tourist Behaviour Predictors: a Focus on Organised Vs. Independent Tourism.

2013

Public-private sector pay gaps in Finland: A quantile regression analysis

2011

This paper examines public-private sector wage differentials in Finland using a quantile regression method. We control for the endogeneity of the working sector and allow the returns of individual skills to vary between industries. The results suggest that men earn a premium of 3 percent in the public sector at the lower-end jobs. At the median and the upper end of the distribution, men’s pay gap is negative, varying between 5 and 10 percent. Women, in turn, always earn more in the public sector (4–10 percent), and the premium is highest at the upper end of the earnings distribution. (JEL: J31, J45) peerReviewed