Bivariate Structural Regression Analysis: A Tool for the Comparison of Analytic Methods

1987 ◽  
Vol 26 (04) ◽  
pp. 205-214 ◽  
Author(s):  
U. Feldmann ◽  
B. Schneider
Keyword(s):  
Regression Analysis ◽  
Clinical Chemistry ◽  
Statistical Tests ◽  
Model Fit ◽  
Likelihood Method ◽  
Distribution Free ◽  
Accuracy And Precision ◽  
Distribution Free Approach ◽  
Structural Regression ◽  
A New Technique

SummaryThis paper introduces the concept of bivariate structural regression analysis, a new technique which offers some advantages compared to the well-known structural relationship approach. The concept is not restricted to multivariate normal distribution, and without additional constraints the model remains identifiable in the bivariate case. A bivariate calibration line is developed first by the maximum likelihood method and then also distribution-free by applying rank statistics. Both estimation procedures coincide, if the distribution assumption is satisfied. Hence, the distribution-free approach has an efficiency of 100%. Our concept of analysis is applied to the comparison of analytical methods in clinical chemistry. Appropriate statistical tests concerning accuracy and precision as well as the model fit are offered.

On assessing model fit for distribution-free longitudinal models under missing data

2013 ◽  
Vol 33 (1) ◽  
pp. 143-157 ◽  
Author(s):  
P. Wu ◽  
X.M. Tu ◽  
J. Kowalski
Keyword(s):  
Missing Data ◽  
Model Fit ◽  
Longitudinal Models ◽  
Distribution Free

Cost and Profit Efficiencies in the Spanish Hotel Industry

2015 ◽  
Vol 41 (8) ◽  
pp. 985-1006 ◽  
Author(s):  
Antonio Arbelo ◽  
Pilar Pérez-Gómez ◽  
Enrique González-Dávila ◽  
Felipe Manuel Rosa-González
Keyword(s):  
Competitive Advantage ◽  
Special Interest ◽  
Cost Efficiency ◽  
Hotel Industry ◽  
Profit Efficiency ◽  
Distribution Free ◽  
Working Hypothesis ◽  
Distribution Free Approach ◽  
Hotel Sector

This article focuses on estimating and discussing cost and profit efficiencies related with the Spanish hotel sector. Managers have a special interest in controlling costs as a source of competitive advantage, which may enable companies to improve their results in a continuous manner. However, they usually do not attribute much importance to the improvement of profit efficiency, which is generally much lower than cost efficiency and as a result vital for achieving competitive advantage. In this article, cost and profit efficiencies are estimated in the Spanish hotel sector using a data panel for the years 2007 to 2011 and using distribution free approach methodology. The results show profit efficiency levels significantly lower than levels of cost efficiency, thereby confirming our working hypothesis.

Factors Influencing Students Intention to Choose Career of Halal Food Industry in Malaysia using Theory of Planned Behavior

2021 ◽  
Vol 8 (1) ◽  
pp. 50-67
Author(s):  
Nashirah Abu Bakar ◽  
Sofian Rosbi ◽  
Hydzulkifli Hashim ◽  
Noraziah Che Arshad
Keyword(s):  
Regression Analysis ◽  
University Students ◽  
Multiple Regression Analysis ◽  
Food Industry ◽  
Behavioral Control ◽  
Subjective Norm ◽  
Model Fit ◽  
Perceived Behavioral Control ◽  
Significant Development ◽  
Halal Food

Background: The food industry in Malaysia has experienced significant development, especially in the halal food sector. The halal food industry is a market segment involved with food items and beverages that are strictly prepared according to rules underlined by the Islamic dietary law. In addition, the concept of halal covers not only Syariah law, but also hygiene, sanitation and food safety requirements. Malaysia has become a major global halal hub in delivering halal food to local and international levels. The significant development of halal food industry in Malaysia creates significant job opportunities for new graduating students.  Therefore, this study aims to evaluate factors that influence student intention to choose a career for the halal food industry in Malaysia. Research Methodology: This study using a quantitative research method with questionnaire development in assessing the factors that influence intention of students to involve in halal food industry as their future career. The underpinning theory is Theory of Planned Behavior (TPB). The independent variables are Attitude (A), Subjective Norm (SN) and Perceived Behavioral Control (PBC). This study developed four questions for each variable. Unit of analysis for respondents is university students in Malaysia. The sample size is 40 students that have an interest in working for halal food industry in Malaysia. The correlation analysis was analyzed using Pearson Correlation coefficient analysis. Meanwhile, the causal relationship was analyzed using multiple regression analysis. Results: The skewness values for four variables in this study are between -1 and +1 that indicates normal distribution. The value of Cronbach’s alpha statistical test for measuring internal reliability is larger than 0.7 for all four variables. Therefore, four constructs exhibit good reliability that indicates the suitability of internal consistency. Next, the value of R-squared for model fit in this study is 0.675 that indicates a good model fit that explained 67.5% of variance in dependent variable. Multiple regression analysis indicates Attitudes (A), Subjective Norm (SN) and Perceived Behavioral Control (PBC) are significant in predicting the value of Intention (I) to select a career in halal food industry. Conclusion: This study supported the hypothesis that indicates there is a positive and significant relationship of Attitude (A), Subjective Norm (SN) and Perceived Behavioral Control (PBC) towards Intention (I). The findings of this study add value to theoretical knowledge of career selection among university students. At the same time, this study provides guideline for government in developing better policy in cultivating interest among university students to be highly involved in the halal food industry.

scholarly journals Pre-analytical quality control in hemostasis laboratories: visual evaluation of hemolysis index alone may cause unnecessary sample rejection

2019 ◽  
Vol 43 (2) ◽  
pp. 67-76
Author(s):  
Simona Storti ◽  
Elena Battipaglia ◽  
Maria Serena Parri ◽  
Andrea Ripoli ◽  
Stefania Lombardi ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Visual Inspection ◽  
Clinical Chemistry ◽  
Linear Regression Analysis ◽  
Reference Method ◽  
Analytical Performance ◽  
Visual Evaluation ◽  
Automated Method ◽  
Visual Index

Abstract Background Visual inspection is the most widespread method for evaluating sample hemolysis in hemostasis laboratories. The hemolysis index (HI) was determined visually (visual index, VI) and measured on an ACL TOP 750 (IL Werfen) system with a hemolysis-icterus-lipemia index (HIL) module. These values were compared with those measured on clinical chemistry systems Unicel DXC600 and AU680 and with quantitation of free-hemoglobin (Hb) performed by a spectrophotometric measurement method (SMM). Methods The HI was measured in 356 sodium citrate plasma samples, 306 of which were visibly hemolyzed to varying degrees and 50 were not hemolyzed. The analytical performance of each method was evaluated. Results Linear regression analysis, calculated between SMM and the other systems in the study, returned coefficients of determination r2 = 0.853 (AU680), r2 = 0.893 (DXC600) and r2 = 0.917 (ACL TOP 750). An r2 = 0.648 was obtained for linear regression analysis between VI and ACL TOP 750. In addition, ACL TOP 750 showed an excellent correlation in multivariate analysis (r2 = 0.958), showing good sensitivity (0.939) and specificity (0.934) and a diagnostic accuracy of 94%. By comparison, DXC600 and AU680 showed coefficients of determination of 0.945 and 0.923, respectively. A cut-off was set at 0.15 g/L free-Hb, as determined by the automated method, such that any hemostasis samples measuring above this threshold should not be analyzed. Based on this criterion, samples were classified as accepted or rejected, and the number of samples discarded during VI or ACL TOP 750 measurements was compared. Conclusions This study confirmed that hemostasis laboratories should consider introducing an objective, automated and standardized method to check samples for hemolysis. By relying solely on visual inspection, up to 50% of samples could be unnecessarily rejected. The ACL TOP 750 system demonstrated a satisfactory analytical performance, giving results comparable to those of the reference method.

A Multimarket Analysis of Inter-dependent Consumer Response Sensitivities

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Sudhir Voleti
Keyword(s):  
Spatial Information ◽  
Consumer Response ◽  
Model Fit ◽  
Improve Model ◽  
Macroeconomic Indicators ◽  
Distribution Free Approach ◽  
Explained Variance ◽  
Market Areas ◽  
The Relationship

AbstractWe investigate variation in aggregate consumer response sensitivities to the price, promotion and distribution elements of the marketing mix across US metropolitan markets. Primarily, three questions of research interest are examined – (i) the nature of the relationship between different aggregate response sensitivities and the implications therein, (ii) the usefulness of aggregate area-wide macroeconomic indicators such as inflation, unemployment and poverty in the context of a marketing problem, and (iii) the usefulness of geo-spatial information under a distribution-free approach. Beer category sales data across 49 major US metropolitan markets are analyzed. We find a pattern of strong inter-dependence among aggregate response sensitivities that indicates the existence of distinct, non-overlapping consumer segments. This enables a characterization of metropolitan market areas at an aggregate level. Ignoring inter-dependence mis-characterizes response sensitivity in two-thirds of the markets sampled. Further, on a standalone basis, neither area-wide economic indicators nor geo-spatial information help the analysis, but in conjunction, they vastly improve model fit (by almost 40%), explained variance (by over twice), parameter significance and consequently, insight.

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