Ordinary Least-squares Regression Analysis Research Articles

Pressure points in reading comprehension: A quantile multiple regression analysis.

The goal of this study was to examine how selected pressure points or areas of vulnerability are related to individual differences in reading comprehension and whether the importance of these pressure points varies as a function of the level of children’s reading comprehension. A sample of 245 third-grade children were given an assessment battery that included multiple measures of vocabulary, grammar, higher-level language ability, word reading, working memory, and reading comprehension. Ordinary least squares (OLS) and quantile regression analyses were undertaken. OLS regression analyses indicated that all variables except working memory accounted for unique variance in reading comprehension. However, quantile regression showed that the extent of the relationships varied in some cases across readers of different ability levels. Results suggest that quantile regression may be a useful approach for the study of reading in both typical and atypical readers and aid greater specification of componential models of reading comprehension across the ability range.

Forest dynamics to precipitation and temperature in the Gulf of Mexico coastal region.

The forest is one of the most significant components of the Gulf of Mexico (GOM) coast. It provides livelihood to inhabitant and is known to be sensitive to climatic fluctuations. This study focuses on examining the impacts of temperature and precipitation variations on coastal forest. Two different regression methods, ordinary least squares (OLS) and geographically weighted regression (GWR), were employed to reveal the relationship between meteorological variables and forest dynamics. OLS regression analysis shows that changes in precipitation and temperature, over a span of 12months, are responsible for 56% of NDVI variation. The forest, which is not particularly affected by the average monthly precipitation in most months, is observed to be affected by cumulative seasonal and annual precipitation explicitly. Temperature and precipitation almost equally impact on NDVI changes; about 50% of the NDVI variations is explained in OLS modeling, and about 74% of the NDVI variations is explained in GWR modeling. GWR analysis indicated that both precipitation and temperature characterize the spatial heterogeneity patterns of forest dynamics.

Mass, phylogeny, and temperature are sufficient to explain differences in metabolic scaling across mammalian orders?

Whether basal metabolic rate‐body mass scaling relationships have a single exponent is highly discussed, and also the correct statistical model to establish relationships. Here, we aimed (1) to identify statistically best scaling models for 17 mammalian orders, Marsupialia, Eutheria and all mammals, and (2) thereby to prove whether correcting for differences in species’ body temperature and their shared evolutionary history improves models and their biological interpretability. We used the large dataset from Sieg et al. (The American Naturalist 174, 2009, 720) providing species’ body mass (BM), basal metabolic rate (BMR) and body temperature (T). We applied different statistical approaches to identify the best scaling model for each taxon: ordinary least squares regression analysis (OLS) and phylogenetically informed analysis (PGLS), both without and with controlling for T. Under each approach, we tested linear equations (log‐log‐transformed data) estimating scaling exponents and normalization constants, and such with a variable normalization constant and a fixed exponent of either ⅔ or ¾, and also a curvature. Only under temperature correction, an additional variable coefficient modeled the influence of T on BMR. Except for Pholidata and Carnivora, in all taxa studied linear models were clearly supported over a curvature by AICc. They indicated no single exponent at the level of orders or at higher taxonomic levels. The majority of all best models corrected for phylogeny, whereas only half of them included T. When correcting for T, the mathematically expected correlation between the exponent (b) and the normalization constant (a) in the standard scaling model y = a x b was removed, but the normalization constant and temperature coefficient still correlated strongly. In six taxa, T and BM correlated positively or negatively. All this hampers a disentangling of the effect of BM, T and other factors on BMR, and an interpretation of linear BMR‐BM scaling relationships in the mammalian taxa studied.

Modelling tourists’ length of stay

Modelling of tourists’ length of stay (LOS) is an expanding topic of study. A common thread in this literature is the use of sophisticated statistical/econometric methods. The present study builds on and extends an article critical of the statistical craftsmanship in prior LOS modelling studies. On the basis of an updated assessment of current practice and two small-scale case studies, two main conclusions are drawn. First, the available evidence suggests that the ordinary least squares (OLS) regression model produces qualitatively similar findings to much more complicated methods, such as duration and count data models. The principle of parsimony and the so-called KISS rule thus dictate that OLS regression analysis should be the preferred estimation technique in LOS modelling studies. Second, the quality of LOS modelling studies will most likely be improved by intensifying the use of the long-established tools of the trade explicated in influential econometric textbooks rather than by testing new estimation methods.

Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns.

To examine whether the association between soft drinks consumption and child behaviour problems differs by food security status and sleep patterns in young children. Cross-sectional observational data from the Fragile Families and Child Wellbeing Study (FFCWS), which collected information on food insecurity, soft drinks consumption, sleep patterns and child behaviour problems. Bivariate and multivariate ordinary least-squares regression analyses predicting child behaviour problems and accounting for socio-economic factors and household characteristics were performed. Twenty urban cities in the USA with a population of 200 000 or more. Parental interviews of 2829 children who were about 5 years old. Soft drinks consumption was associated with aggressive behaviours, withdrawn and attention problems for children aged 5 years. However, the association differed by food security status. The association was mostly statistically insignificant among food-secure children after accounting for socio-economic and demographic characteristics. On the other hand, soft drinks consumption was associated with behaviour problems for food-insecure children even after accounting for these factors. However, after accounting for child sleep patterns, the association between soft drinks consumption and child behaviour problems became statistically insignificant for food-insecure children. The negative association between soft drinks consumption and child behaviour problems could be explained by sleep problems for food-insecure children. Since about 21 % of households with children are food insecure, targeted efforts to reduce food insecurity would help improve dietary (reduce soft drinks consumption) and health behaviours (improve sleep) and reduce child behaviour problems.

Accounting for variation in perception of police

Drawing on data collected from a survey of 334 randomly selected residents in Ile-Ife, Nigeria, this paper explores the perception and factors that contributed to residents’ opinion of the police. The overall result revealed that residents had low satisfaction with the police. It was deducible that satisfaction with the police increases with an increase in residents’ level of education, income status and age. Furthermore, maximum satisfaction was held about the police by residents who felt very much safe in the study area. It was further revealed that satisfaction with the police increases as place of residence changes from a high- to a low-density neighbourhood. The result of multiple ordinary least-squares regression analysis further revealed gender, experience of crime and contact with the police as significant factors in residents’ perception of the police. The study therefore concluded that perception of the police varies between socioeconomic groups and is also influenced by many other contextual factors.

The impact of executives’ perceptions of environmental threats and organizational slack on innovation strategies

Purpose The paper aims to study the relationship between executives’ perceptions of environmental threats and innovation strategies and investigate the moderating effect of contextual factor (i.e. organizational slack) on such relations. It proposes a dualistic relationship between executives’ perceptions of environmental threats and innovation strategies, in which different perceptions of environmental threats will lead to corresponding innovation strategies, and dyadic organizational slack can promote such processes. Design/methodology/approach The paper is based on a survey with 163 valid questionnaires, which were all completed by executives. Hierarchical ordinary least-squares regression analysis is used to test the hypotheses proposed in this paper. Findings The paper provides empirical insights about that executives tend to choose exploratory innovation when they perceive environmental changes as likely loss threats, yet adopt exploitative innovation when perceiving control-reducing threats. Furthermore, unabsorbed slack (e.g. financial redundancy) positively moderates both relationships, while absorbed slack (e.g. operational redundancy) merely positively influences the relationship between the perception of control-reducing threats and exploitative innovation. Originality/value The paper bridges the gap between organizational innovation and cognitive theory by proposing a dualistic relationship between executives’ perceptions of environmental threats and innovation strategies. The paper further enriches innovation studies by jointly considering both subjective and objective influence factors of innovation and argues that organizational slack can moderate such dualistic relationship.

Diagnostic Challenge

This study investigated the relative importance of three subdomains of early number competence (number, number relations, and number operations) in predicting later mathematics achievement in cross-sequential samples of pre-kindergarten (pre-K), kindergarten, and first-grade children (n = 150 at each grade). Ordinary least-squares (OLS) regression analyses showed that each subdomain predicted mathematics achievement at each grade level, controlling for the other two subdomains as well as background variables. All the subdomains explained a significant amount of variance in later mathematics achievement. Unconditional quantile regression analyses examined relations between number competencies and mathematics achievement at quantiles representing low (0.2), intermediate (0.5) and high (0.8) achievement. The subdomain of number operations was highly related to mathematics achievement for high achievers. For low achievers, future mathematics achievement was most highly related to number and number relations abilities in the pre-K sample and to number relations abilities in the kindergarten and first-grade samples. Findings highlight the unique importance of all three subdomains of early number competence for later mathematics achievement, but they show that some of the relations are contingent on achievement level.

Trends in prescription of pregnancy-contraindicated drugs in Korea, 2007–2011

This study aims to evaluate changes in use of contraindicated drugs during pregnancy in Korea using the nationwide Health Insurance and Assessment Service (HIRA) database. Study drugs were 314 drugs that were announced as pregnancy-contraindicated on December 11, 2008. The study population consisted of the pregnant women who gave birth and were prescribed any of the drugs in 2007–2011 before giving birth. Pregnancy-contraindicated drug use was defined as the proportion of prescriptions among pregnant women that were for study drugs. The relative and absolute reductions in contraindicated drug use after the 2008 action were estimated with 95% confidence interval (CI) by medical institution type, region, and drug class. The predicted monthly contraindicated drug use was estimated by performing ordinary least-squares regression analysis of data before the action and compared with observed data after the action. Between 2007 and 2011, a total of 1,468,588 pregnant women received 1,796,208 prescriptions. Contraindicated drug use accounted for 15.96% of total prescriptions (N = 355,783) before the action but decreased to 11.52% (N = 453,832) afterward. Overall, the relative reduction was 27.77% (95% CI: 27.64%–27.90%) and greatest for hormones at 46.56% (95% CI: 46.21%–46.93%). The relative reduction was 55.43% (95% CI: 54.60%–55.43%) for all category X drugs, 17.09% (95% CI: 16.46%–17.75%) for category X drugs excluding hormones, and 0.14% (95% CI: 0.14%–0.15%) for category D drugs including hormones. A regulatory action toward pregnancy-contraindicated drugs led to moderate decrease in contraindicated drug use during pregnancy. Despite the decreases, contraindicated drugs were still widely prescribed to pregnant women, highlighting the need to develop strategies to assess and improve drug safety during pregnancy.

The impact of the megafauna extinctions on savanna woody cover in South America

Has land surface cover in South America been impacted by the loss of most large herbivores following the severe Pleistocene and Early Holocene megafauna extinctions on this continent? Here, we estimate how mean savanna woody biomass may have changed in the Americas following these extinctions by creating an empirical model to understand how large herbivores impact savanna woody biomass. To create this empirical model, we combine a large recently published dataset of savanna woody cover from Lehmann et al. (2014) (n = 2154 plots) with estimates of mammals ranges and weights from the IUCN database. We evaluate how variables such as number of megaherbivores (mammal species ≥ 1000 kg), log10 sum species weights, and total number of mammal species predict changes to woody cover by using both ordinary least squares regression analysis (OLS) and simultaneous auto‐regressive (SAR) analysis to control for spatial autocorrelation. Both number of megaherbivores and log10 sum species weights, which both disproportionately weight for megaherbivores, significantly explained much (∼ 5–13%) variance in woody cover, but the third variable weighting all animals equally, did not. We then combined these biotic variables with abiotic variables such as temperature, precipitation, and fire frequency to create a model predicting 36% of the variance of savanna woody cover. We used this model combined with estimated range maps of extinct South American megafauna to estimate that had those South American megafauna not gone extinct, total savanna woody cover in South America could possibly have decreased by ∼ 29% and that savannas would likely have been more open like current African savannas.

Household capacity to adapt to climate change and implications for food security in Trinidad and Tobago

We investigate household-level food security in the face of climatic change in coastal wetland-situated households in Trinidad and Tobago. These communities rely heavily, but not solely, on natural resources and agriculture for their livelihoods. Household data were collected for a representative sample of 138 households in the Nariva and Caroni communities. This included data on household adaptive capacity including socio-demographics, livelihood strategies, and social networks; exposure to climate change and climate-induced extreme weather events, such as floods and droughts; and sensitivity factors related to local access to services and infrastructure. Using ordinary least-squares regression analyses, we investigate influences of adaptive capacity to climate change on household food security in these ‘at-risk’ communities. The results suggest that household socio-demographics and livelihood strategies are strongly related to food security and that the level of food security provided by those two factors is reduced in the face of climate variability and disaster. Social network capacity of households does not have a statistically significant influence in the context studied. This is a valuable insight for community and national planners and policy makers both in this and in similar country circumstances that must consider food security in light of climate variability and related weather-induced impacts.

The relationships that matter: social network site use and social wellbeing among older adults in the United States of America

ABSTRACTAn increasing number of middle-aged and older Americans are using social network sites (SNSs), but little research has addressed how SNS use is associated with social wellbeing outcomes in this population. Using a nationally representative sample of 1,620 Americans older than 50 from the 2012 Health and Retirement Study (HRS), we examine the relationship between older adults’ SNS use and social wellbeing associated with non-kin and kin relations and explore how these associations vary by age. Results of ordinary least-squares regression analyses suggest that SNS use is positively associated with non-kin-related social wellbeing outcomes, including perceived support from friends (β = 0.13;p< 0.001; N = 460) and feelings of connectedness (β = 0.10;p< 0.001; N = 463). Regression models employing interaction terms of age and SNS use further reveal that SNS use contributes to feelings of connectedness to a greater extent as people age (β = 0.10;p< 0.001; N = 463). Of all kin-related social wellbeing outcomes, SNS use only predicts increased perceived support from children (β = 0.08;p< 0.05; N = 410), and age negatively shapes this relationship (β = −0.14;p< 0.001; N = 410). As older people engage with an increasingly smaller and narrower network with a greater proportion of kin contacts, our results suggest that SNS use may help older adults access differential social benefits throughout later life.

The stability of coping strategies in older adults with osteoarthritis and the ability of these strategies to predict changes in depression, disability, and pain

Objectives: Given the chronically painful, incurable nature of osteoarthritis, effective cognitive and behavioral coping strategies may be critical for older adults with the disease. Little is known about how and why coping changes over time, nor about stability of coping strategies in persons with osteoarthritis. The aims of this work were to examine the structure of coping in older adults with osteoarthritis, the association of coping strategies with well-being, the stability of coping over time, and its association with changes in well-being over the same period.Method: In a cross-sectional study, 199 older adults with osteoarthritis of the knee were assessed at baseline and two-years’ follow-up. Items from two coping scales were factor analyzed, and Pearson's correlations and paired-samples t-tests assessed relative and absolute stability of the resultant coping strategies. CFA assessed the stability of the factor structure itself. Ordinary least-squares regression analyses examined the impact of change in coping on well-being.Results: A five-factor coping solution emerged: stoicism, refocusing, problem-solving, wishful-thinking, and emotion-focused coping. The factor structure showed stability over the two-year period. Absolute stability of strategies varied, indicating that change in coping styles was possible.Conclusion: Changes in coping style predicts future well-being; however, coping remains malleable with age and maladaptive strategies can be effectively targeted. Greater knowledge of the utility or maladaptive nature of a given strategy may help guide decisions about interventions for patients with osteoarthritis and encourage more adaptive coping styles.

Regression Analysis: Instructional Resource for Cost/Managerial Accounting

This paper describes a classroom-tested instructional resource, grounded in principles of active learning and a constructivism, that embraces two primary objectives: ‘demystify’ for accounting students technical material from statistics regarding ordinary least-squares (OLS) regression analysis – material that students may find obscure or overly abstract – and increase student knowledge regarding the use of Excel for cost-estimation purposes. The resource consists of a set of seven student-related files – PowerPoint slides, Word documents, and Excel files – divided into two major parts: four files that deal with simple (i.e., one-variable) linear regression and three files related to the incremental unit-time learning-curve model. A separate Word file, meant for instructors, provides detailed guidance regarding the use of the student-based files. The resource is flexible in that it can be used at both graduate and undergraduate courses in cost/management accounting; customized to meet the needs of individual instructors (coverage of the entire resource requires approximately seven hours of in-class time) and used in conjunction with any cost/management accounting textbook. Throughout the resource many references to related online supplemental materials are provided, including links to relevant online video clips.

Attitudes, Opinions, and Characteristics: Creating a Profile of Sales Students

This study was conducted with the objective of identifying and assessing factors that influence students to have a disposition toward a sales career as well as positive attitudes toward salespeople. Two studies were conducted to measure the impact of different treatments. Data were collected from 263 undergraduate students in marketing and/or sales-related classes, in order to empirically test two experiments. The results of ordinary least-squares regression analysis indicate that students enrolled in sales-related classes are much more likely to have a disposition toward a sales career and to have a positive attitude toward salespeople, while simply reading a passage describing the sales profession and how it is likely for many college graduates to have a career in sales had little impact. The implications include the development of a sales students’ profile, which describes students who are likely to pursue sales as a career and to have a positive attitude toward salespeople. This profile can be important in identifying potentially successful members of professional sales forces while they are still in our universities and by doing so, enable sales educators to properly prepare them for their careers.

What explains functioning from the perspective of people with multiple sclerosis?

The Brief International Classification of Functioning, Disability and Health (ICF) Core Set for MS was developed to capture functioning in people with multiple sclerosis (pwMS). This study examined whether categories in the Brief ICF Core Set for MS best capture different levels of functioning in pwMS. We used data of a multicenter cross-sectional study collected from 205 pwMS using the ICF categories of the MS-specific WHO ICF Checklist and the individual rating of functioning. ICF categories to be entered in an initial regression model were selected following a systematic procedure in accordance with the ICF structure. Based on the initial regression model using stepwise Ordinary Least-Squares regression analyses, additional models were designed by substituting the ICF categories in final model. The selected set of categories was compared with the Brief ICF Core Set for MS. Eleven ICF categories were identified that best differentiate among different levels of functioning. Four were part of the Brief ICF Core Set. ICF categories identified in this study may be used as outcome measures in further study, parameters to monitor functioning along the continuum of health care and lifespan, and to define different subgroups of pwMS.

Estimating farmers patronage level of informal credit in Imo State: Implication for efficient formal and informal financial linkage and rural development

Low agricultural productivity in Imo State is blamed on poor grassroot financial development. Farmers are caught between maginalization, clumsy, costly and grossly inefficient credit delivery system. An efficient informal credit patronage that engenders informal-formal credit linkage system in Imo State was investigated. Data were collected from 59 arable crop farmers and 15 Informal Financial Agencies (IFAs) in Imo State and analysed using both descriptive ststistics and econometric tools such as frequency/means and Ordinary Least Square regression analysis (OLS) respectively. The result showed that 93.2% of the farmers must have accessed credit from town union/age grade while 55.5 and 33.9% were with Esusu and cooperatives respectively. The mean informal credit patronage ratio of 0.712, ranging from 0.64 (town unions) to 0.97 (esusu groups) was recorded. Average loan of N12,756.61 (town unions) to N12,959.79 (esusu) was obtained. Though there were disbursement with more members in the town unions yet the level of credit patronage was highest (97.0%) with esusu group of farmers. Increase in education, farming experience, household size and social capital each has a significant and positive effect on informal credit patronage while interest rate reduces it. It is recommended that the formal credit sectors should cash on this high informal credit patronage to market loan facilities to informal credit agencies at a lower cost for an informal-formal credit linkage. Key words: Patronage, coperative, esusu, town union, formal and informal linkage and credit delivery.

STRESS-COPING STRATEGIES OF HIGHER EDUCATION OF THE ACADEMIC AND NON-ACADEMIC STAFF IN EASTERN VISAYAS

Stress susceptibility, sources and symptoms have something to do with how employees in the workplace respond to varied situations. When not dealt with properly stress would lead to non-performance of the employees and low productivity of the organization. Hence, a descriptive survey was conducted to determine the stress profile and coping strategies of the academic and administrative staff of the selected public and private Higher Education Institutions (HEIs) in Eastern Visayas. On average, a significant difference in the stress profile is manifested between the academic staff and administrative staff in the public HEIs while no difference is shown in the private HEIs. Ordinary least-squares regression analysis identified income, educational qualification, stress susceptibility and stress symptoms as predictors to stress. To regulate one’s susceptibility to stress and mitigate stress sources, the respondents used a wide range of coping mechanisms which disclosed a significant difference between the academic and administrative staff in private HEIs. The coping strategies of academic and administrative staff in public HEIs were observed to have no difference. Knowing the predictors to stress and the varied coping strategies used by the HEI employees in Region 8, a Stress Management Program is hereby suggested for adoption and implementation.

English

This study was carried out with the aim to find out the level and socio-economic determinants of the adoption of New Rice for Africa (NERICA) using Ewekoro Local Government Area of Ogun State in Nigeria as a case study. One hundred and sixteen rice farmers were randomly selected in this area, twenty eight of which adopted NERICA rice varieties within 2009/2010 cropping season. Information was gathered through the use of well structured questionnaire and personal interview of the farmers. Descriptive statistics, ordinary least-squares (OLS) regression analysis and T-test statistics were used for the analysis of the data collected. It was discovered through the findings that the rate of adoption was 33.36%, while the socio-economic determinants of the adoption of the technologies include farming experience, age of the farmer, frequency of contact with the officials of Agricultural Development Programme (ADP) in the state and farm size. Moreover, the findings show that the nonadopters of NERICA technological package had higher average output and average yield than the adopters of the technologies. Lastly, the study gave valuable recommendations which could be helpful toward enhancing improved rate of adoption of NERICA rice technologies by the farmers in the study area.

Gender Wage Differences and Illicit Drug Use: Findings from Yunnan Province

This work compares differences in income between men and women in Yunnan, a southwestern province in China, in 2003. The data collection, conducted by co-authors Yang and Luo, was funded by the National Institute on Drug Abuse. The focus is on how illicit drug use shapes gender wage differences. Little research has been conducted which examines how drug use shapes wage differences in China and the existing work that does explore this relationship in the United States yields mixed results. Utilising basic ordinary least-squares (OLS) regression analysis, differences in earnings (log income) were examined, controlling variables for drug use, experience, marital status, educational attainment, Communist Party membership and other background variables. The data provide supporting evidence that current drug users reported higher income compared to others, all else being equal.