scholarly journals Agricultural Economists' Effectiveness in Reporting and Conveying Research Procedures and Results

2000 ◽  
Vol 29 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Joe L. Parcell ◽  
Terry L. Kastens ◽  
Kevin C. Dhuyvetter ◽  
Ted C. Schroeder
Keyword(s):  
Regression Analysis ◽  
Degrees Of Freedom ◽  
Statistical Significance ◽  
Resource Economics ◽  
Economic Importance ◽  
Parameter Estimates ◽  
Summary Statistics ◽  
Economic Significance ◽  
Fourth Report

This study reviews articles using regression analysis published in the Journal of Agricultural and Resource Economics from 1994 to 1998 to determine agricultural economists’ effectiveness in reporting and conveying research procedures and results. Based on the authors’ experiences of surveying articles for this study, several suggestions for reporting of results and how to better separate statistical from economic significance are offered. First, clearly define the dependent variable—preferably in the results table as well as within the text. Second, report parameter estimates in an interpretable form either in the results table or in a subsequent table. Third, report summary statistics. Fourth, report degrees of freedom conspicuously in the results table. Fifth, report if statistically insignificant variables have been dropped. Lastly, weigh economic importance aside from statistical significance and use simulation to express economic significance where appropriate.

The Relationship Between The Perception of Elderly’s Health Status and Health Behaviors in Nakhon Nayok Province, Thailand

2019 ◽  
Vol 12 (1) ◽  
pp. 420-423
Author(s):  
Prapada Watcharanat ◽  
Prasong Tanpichai ◽  
Ravee Sajjasophon
Keyword(s):  
Regression Analysis ◽  
Health Status ◽  
Health Behaviors ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Statistical Significance ◽  
The Elderly ◽  
Cross Sectional ◽  
Congenital Diseases ◽  
The Relationship

Purpose: This research aims to study the relationship between perception of elderly’s health and health behaviors in Nakhon Nayok province, Thailand Methods: This research was a cross-sectional study. The questionnaire was used to collect the data. This research was conducted in Nakhon Nayok province. The sample size was 270 which applied Taro Yamane's formula at a significant level 0.05. The descriptive statistics was implemented to describe the variables by presenting the frequency, percentage, mean and standard deviation. Furthermore, multiple regression analysis was applied to analyze the relationship between perception of elderly’s health and health behaviors. The statistical significance was considered to reject Hypothesis-null at < 0.05. Results: From a total of 270 people, more than 58.22% of the elderly perceived that they had moderate health conditions. Most elderly had congenital diseases (62.2%). The multiple regression analysis results showed that health status perception and health status perception when compared to their cohort related significantly to health behavior. Conclusion: The government should support the elderly on participation, trust, engagement, and cultural concern of the people in the community, which can contribute to promoting the physical, mental and social condition of the elderly.

Standard Asymptotic Theory

2017 ◽  
Author(s):  
Russell Cheng
Keyword(s):  
Asymptotic Theory ◽  
Asymptotic Variance ◽  
Statistical Significance ◽  
Regularity Conditions ◽  
Parameter Estimates ◽  
Asymptotic Results ◽  
Ml Estimation ◽  
True Parameter ◽  
Log Likelihood ◽  
Ml Estimator

This book relies on maximum likelihood (ML) estimation of parameters. Asymptotic theory assumes regularity conditions hold when the ML estimator is consistent. Typically an additional third derivative condition is assumed to ensure that the ML estimator is also asymptotically normally distributed. Standard asymptotic results that then hold are summarized in this chapter; for example, the asymptotic variance of the ML estimator is then given by the Fisher information formula, and the log-likelihood ratio, the Wald and the score statistics for testing the statistical significance of parameter estimates are all asymptotically equivalent. Also, the useful profile log-likelihood then behaves exactly as a standard log-likelihood only in a parameter space of just one dimension. Further, the model can be reparametrized to make it locally orthogonal in the neighbourhood of the true parameter value. The large exponential family of models is briefly reviewed where a unified set of regular conditions can be obtained.

scholarly journals LDH, CRP and ALB predict nucleic acid turn negative within 14 days in symptomatic patients with COVID-19

2021 ◽  
pp. 003693302199424
Author(s):  
Gaoli Liu ◽  
Bicheng Zhang ◽  
Shaowen Zhang ◽  
Haifeng Hu ◽  
TingTing Liu
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Nucleic Acid ◽  
Hospital Stay ◽  
Prognostic Marker ◽  
Roc Curve ◽  
Prognostic Value ◽  
Statistical Significance ◽  
Biochemical Indicators ◽  
The Relationship

Aims To search for biochemical indicators that can identify symptomatic patients with COVID-19 whose nucleic acid could turn negative within 14 days, and assess the prognostic value of these biochemical indicators in patients with COVID-19. Patients and methods We collected the clinical data of patients with COVID-19 admitted to our hospital, by using logistic regression analysis and AUC curves, explored the relationship between biochemical indicators and nucleic acid positive duration, the severity of COVID-19, and hospital stay respectively. Results A total of two hundred and thirty-three patients with COVID-19 were enrolled in the study. We found patients whose nucleic acid turned negative within 14 days had lower LDH, CRP and higher ALB ( P < 0.05). ROC curve results indicated that lower LDH, TP, CRP and higher ALB predicted the nucleic acid of patients turned negative within 14 days with statistical significance( P < 0.05), AST, LDH, CRP and PCT predicted the severe COVID-19 with statistical significance, and CRP predicted hospital stay >31days with statistical significance ( P < 0.05). After verification, the probability of nucleic acid turning negative within 14 days in patients with low LDH (<256 U/L), CRP (<44.5 mg/L) and high ALB (>35.8 g/L) was about 4 times higher than that in patients with high LDH, CRP and low ALB ( P < 0.05). Conclusions LDH, CRP and ALB are useful prognostic marker for predicting nucleic acid turn negative within 14 days in symptomatic patients with COVID-19.

scholarly journals Prevalence and Factors Associated with Interpersonal Violence among In-School Adolescents in Ghana: Analysis of the Global School-Based Health Survey Data

Adolescents ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 186-198
Author(s):  
Richard Gyan Aboagye ◽  
Abdul-Aziz Seidu ◽  
Francis Arthur-Holmes ◽  
James Boadu Frimpong ◽  
John Elvis Hagan ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Health Survey ◽  
Interpersonal Violence ◽  
Statistical Significance ◽  
Final Analysis ◽  
Risky Behaviors ◽  
Health Concern ◽  
Negative Consequences ◽  
Factors Associated ◽  
School Based

Interpersonal violence is a critical public health concern that is linked with many negative consequences, including mortality. It is the second most predominant cause of death among male adolescents aged 15–19. This study used a nationally representative data from the recent Ghana Global School-based Health Survey to examine the prevalence and factors associated with interpersonal violence among Ghanaian in-school adolescents. A total of 2214 in-school adolescents were included in the final analysis. Multivariable binomial logistic regression analysis was performed to determine the factors assciated with interpersonal violence. The results of the regression analysis were presented as adjusted odds ratios (aOR) with 95% confidence level (CI) in all the analyses. Statistical significance was set at p < 0.05. The overall prevalence of interpersonal violence was 55.7%, of which the prevalences of physical fighting and attack were 38.2% and 41.5%, respectively. In-school adolescents who had an injury were more likely to experience interpersonal violence (aOR = 2.29, 95% CI = 1.71–3.06) compared with those who did not have an injury. The odds of interpersonal violence were higher among in-school adolescents who were bullied (aOR = 2.48, 95% CI = 1.84–3.34) compared with those who were not bullied. In addition, in-school adolescents who attempted suicide (aOR = 1.56, 95% CI = 1.22–2.47), consumed alcohol at the time of the survey (aOR = 1.88, 95% CI = 1.15–3.06), and were truant (aOR = 1.58, 95% CI = 1.29–1.99) had higher odds of experiencing interpersonal violence. These factors provide education directors and school heads/teachers with the relevant information to guide them in designing specific interventions to prevent interpersonal violence, particularly physical fights and attacks in the school settings. School authorities should organize parent–teacher meetings or programs to help parents improve their relationships with in-school adolescents to prevent or minimize their risky behaviors, including physical fights.

Tourmaline concentrations in Proterozoic sediments of the southern Cordillera of Canada and their economic significance

1977 ◽  
Vol 14 (10) ◽  
pp. 2348-2363 ◽  
Author(s):  
V. G. Ethier ◽  
F. A. Campbell
Keyword(s):  
Heat Flow ◽  
Sedimentary Rocks ◽  
Local Area ◽  
Economic Importance ◽  
Coarse Grained ◽  
Economic Significance ◽  
Lower Proterozoic ◽  
Lead Zinc ◽  
High Boron ◽  
Boron Level

Local concentrations of tourmaline occur in the lower Proterozoic (Helikian) Aldridge Formation of southeastern British Columbia, in some places in association with stratiform lead–zinc mineralization as at the Sullivan, Stemwinder, and North Star orebodies. The amount of boron in the rock is as much as two orders of magnitude above average levels reported for the Aldridge Formation or other similar types of sedimentary rocks. The concentrations are not detrital, but are caused by an anomalously high boron level, in a local area, at the time of sedimentation. The appearance of tourmaline within rip-up clasts, and in laminae within pebbles, is evidence of syngenetic introduction of boron.Three populations of tourmalines, on the basis of composition as determined by microprobe analyses, are described from the area:(1) A Proterozoic stock intruding the Aldridge Formation contains abundant schorl.(2) A tourmaline intermediate in composition between dravite and schorl is typical of Aldridge metasediments. Texturally this type occurs as (a) fine felted aggregates in the footwall of the Sullivan orebody, (b) disseminated through waste beds, and (c) in local concentrations removed from the Sullivan orebody.(3) Coarse-grained recrystallized tourmaline associated with the Sullivan ore is magnesium-rich. Recrystallization is erratic, and is probably related to uneven heat flow during metamorphism and to differences in bulk composition.The economic importance of tourmaline concentrations in the Aldridge Formation is their association in both space and time with stratiform sulfides.

scholarly journals Abdominal Wall Injuries at the Elite Level in Australian Male Professional Cricketers

2015 ◽  
Vol 49 (4) ◽  
pp. 155-158 ◽  
Author(s):  
David Humphries ◽  
John Orchard ◽  
Alex Kountouris
Keyword(s):  
Risk Factors ◽  
Regression Analysis ◽  
Abdominal Wall ◽  
Data Extraction ◽  
Statistical Significance ◽  
Significant Risk ◽  
Oblique Muscle ◽  
Minimal Risk ◽  
Risk Increase ◽  
Elite Level

ABSTRACT Background Injuries to the abdominal wall, particularly muscular injuries, are relatively common in professional cricketers. The Cricket Australia injury database holds data on these injuries over a 20 years span. Methods This study is a combination of (1) a descriptive outline of the parameters associated with side strains and abdominal wall injuries in elite male cricketers, based on deidentified data extraction from the Cricket Australia database from 1995 to 1996 and 2014 to 2015; (2) multivariate regression analysis of risk factors for abdominal wall strains, taking into account the risk factors of player position, player age and previous abdominal wall injury history. Results There were 183 injuries recorded over a 20 years period at Australian state or national player level. Significant risk factors in logistic regression analysis were: being a Pace Bowler RR 10.0 (95% CI 3.1—32.1) and being 24 years old or younger RR 3.4 (95% CI 1.7—6.8). Surprisingly, there was only minimal risk increase, not reaching statistical significance, for recent injury in the same season (p = 0.18) and no association at all with past injury in previous season (p = 0.99). Discussion The internal oblique muscle is reported the most commonly injured component of the abdominal wall, the injuries are overwhelmingly sustained by pace bowlers and the peak incidence of the injury is in the early part of the cricket season. Younger fast bowlers are more likely to be injured than older ones. A history of abdominal wall strain in either the recent or distant past does not increase or decrease future risk of strain, which is in contrast to other muscle strains. How to cite this article Humphries D, Orchard J, Kountouris A. Abdominal Wall Injuries at the Elite Level in Australian Male Professional Cricketers. J Postgrad Med Edu Res 2015;49(4): 155-158.

Abstract 19123: Elevated Growth and Differentiation Factor 15 (GDF15) Levels Predict Outcome in Patients With Severe Aortic Stenosis Undergoing Tavi

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Nora Krau ◽  
Sandra Freitag-Wolf ◽  
Doreen Brehm ◽  
Rainer Petzina ◽  
Georg Lutter ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Aortic Valve ◽  
Risk Stratification ◽  
Transforming Growth Factor ◽  
Cox Regression ◽  
Severe Aortic Stenosis ◽  
Statistical Significance ◽  
Cox Regression Analysis ◽  
Negative Outcome

Background: GDF15 belongs to the transforming growth factor superfamily and has a significant role in regulating inflammatory and apoptotic pathways. GDF15 is an emerging biomarker for risk stratification in cardiovascular disease. Here we analyze its prognostic value in patients with severe symptomatic aortic valve stenosis undergoing transcatheter aortic valve implantation (TAVI). Methods and Results: We prospectively enrolled 217 patients undergoing TAVI (using Edwards Sapien XT prostheses) at our institution over a continuous period of 35 month (2/2011-12/2013). All patients were available for complete follow up. Clinical parameters were determined before the procedure, biomarkers (GDF15 & NTproBNP) were measured before, 3 and 7 days after TAVI. The primary endpoint was survival time, all available prognostic factors were studied by Cox regression analysis with backward selection based on the likelihood ratio criteria. At median follow-up of 349 d (Q1-Q3 106-660d), a total of n=66 deaths occurred. 30d mortality was 6.9%. Mean age was 81.8 years (± 6.0 y) and 55.8% were females. Mean log. Euroscore (ES) was 25.4% (± 17.2%). Median preprocedural GDF15 values were 2256 pg/ml (Q1-Q3 1585.5-3082.0). In univariate analyses, increased GDF15 levels (upper quartile compared to lower three quartiles) revealed a HR of 2.4 (CI 1.5-3.9, p<0.001) for adverse outcome. In addition, also log. ES (p= 0.001), log. ES II (p=0.018), STS-Score (p=0.019), NTproBNP (p=0.037) and atrial fibrillation (p=0.02) demonstrated statistical significance for negative outcome. A multivariate Cox regression analysis including these factors and postprocedural aortic regurgitation, demonstrated that elevated GDF15 had a HR of 2.104 (CI 1.3-3.5; p=0.003) for negative outcome in patients undergoing TAVI, while elevated NTproBNP had HR of 1.412 (CI 0.8-2.4; p=0.212). Moreover, this analysis also revealed the log. ES as an independent risk factor (HR of 2.211, CI 1.3-3.7; p= 0.002). Conclusion: Increased GDF15 levels are associated with a poor prognosis in patients undergoing TAVI. Furthermore, GDF15 showed to be superior to the established biomarker NTproBNP in risk stratification of patients undergoing TAVI providing additional prognostic information.

Parameter Estimation in Marketing Models in the Presence of Influential Response Data: Robust Regression and Applications

1984 ◽  
Vol 21 (3) ◽  
pp. 268-277 ◽  
Author(s):  
Vijay Mahajan ◽  
Subhash Sharma ◽  
Yoram Wind
Keyword(s):  
Parameter Estimation ◽  
Regression Analysis ◽  
Least Squares ◽  
Robust Regression ◽  
Ordinary Least Squares ◽  
Regression Coefficients ◽  
Parameter Estimates ◽  
Response Data ◽  
Marketing Models ◽  
Marketing Data

In marketing models, the presence of aberrant response values or outliers in data can distort the parameter estimates or regression coefficients obtained by means of ordinary least squares. The authors demonstrate the potential usefulness of the robust regression analysis in treating influential response values in marketing data.

Adaptive Mismatch Compensation for Rate Integrating Vibratory Gyroscopes With Improved Convergence Rate

2014 ◽  
Author(s):  
Fu Zhang ◽  
Ehsan Keikha ◽  
Behrooz Shahsavari ◽  
Roberto Horowitz
Keyword(s):  
Convergence Rate ◽  
Degrees Of Freedom ◽  
Rotation Angle ◽  
Least Square ◽  
Parameter Estimates ◽  
Unknown Parameters ◽  
Least Square Estimator ◽  
Vibratory Gyroscopes ◽  
Adaptive Compensator ◽  
Simulation Results

This paper presents an online adaptive algorithm to compensate damping and stiffness frequency mismatches in rate integrating Coriolis Vibratory Gyroscopes (CVGs). The proposed adaptive compensator consists of a least square estimator that estimates the damping and frequency mismatches, and an online compensator that corrects the mismatches. In order to improve the adaptive compensator’s convergence rate, we introduce a calibration phase where we identify relations between the unknown parameters (i.e. mismatches, rotation rate and rotation angle). Calibration results show that the unknown parameters lie on a hyperplane. When the gyro is in operation, we project parameters estimated from the least square estimator onto the hyperplane. The projection will reduce the degrees of freedom in parameter estimates, thus guaranteeing persistence of excitation and improving convergence rate. Simulation results show that utilization of the projection method will drastically improve convergence rate of the least square estimator and improve gyro performance.

scholarly journals Sampling Errors in the Measurement of Rainfall Parameters Using the Precipitation Occurrence Sensor System (POSS)

2007 ◽  
Vol 24 (2) ◽  
pp. 125-140 ◽  
Author(s):  
B. E. Sheppard
Keyword(s):  
Doppler Radar ◽  
Statistical Significance ◽  
Time Estimation ◽  
Sensor System ◽  
Parameter Estimates ◽  
Problem Analysis ◽  
Sampling Errors ◽  
Precipitation Occurrence ◽  
Occurrence Type ◽  
Raindrop Size

Abstract The Precipitation Occurrence Sensor System (POSS) is a small Doppler radar originally designed by the Meteorological Service of Canada (MSC) to report the occurrence, type, and intensity of precipitation in automated observing stations. It is also used for real-time estimation of raindrop size distributions (DSDs). From the DSD, various rainfall parameters can be calculated and relationships established, such as between the radar reflectivity factor (Z) and the rainfall rate (R). Earlier work presented first-order estimates of the sampling errors for some POSS rainfall parameter estimates. This work combines a Monte Carlo simulation and “inverse problem” analysis to better estimate errors due to the specific sampling problems of this disdrometer type. The uncertainties are necessary to determine the statistical significance of differences between DSD estimates by the POSS and other collocated disdrometers, or between POSS measurements in different climatologies. Additionally, confidence limits can be assigned to regression coefficients for rainfall parameter relationships determined from POSS estimates. An example is given of the uncertainties in the coefficients of measured Z–R relationships.

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