scholarly journals Likelihood and its use in Parameter Estimation and Model Comparison

2016 ◽  
Vol 37 (3) ◽  
pp. 63-98 ◽  
Author(s):  
Denis Cousineau ◽  
Teresa A. Allan
Keyword(s):  
Parameter Estimation ◽  
Model Comparison ◽  
Regression Line ◽  
Model Fitting ◽  
Estimation Method ◽  
Test Statistics ◽  
Likelihood Methods ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test

Parameter estimation and model fitting underlie many statistical procedures. Whether the objective is to examine central tendency or the slope of a regression line, an estimation method must be used. Likelihood is the basis for parameter estimation, for determining the best relative fit among several statistical models, and for significance testing. In this review, the concept of Likelihood is explained and applied computation examples are given. The examples provided serve to illustrate how likelihood is relevant, and related to, the most frequently applied test statistics (Student’s t-test, ANOVA). Additional examples illustrate the computation of Likelihood(s) using common population model assumptions (e.g., normality) and alternative assumptions for cases where data are non-normal. To further describe the interconnectedness of Likelihood and the Likelihood Ratio with modern test statistics, the relationship between Likelihood, Least Squares Modeling, and Bayesian Inference are discussed. Finally, the advantages and limitations of Likelihood methods are listed, alternatives to Likelihood are briefly reviewed, and R code to compute each of the examples in the text is provided.

scholarly journals Possibility to predict the development of secondary depression in primary alcoholics during abstinence

2005 ◽  
Vol 62 (11) ◽  
pp. 833-839 ◽  
Author(s):  
Gordana Mandic-Gajic
Keyword(s):  
Alcohol Withdrawal ◽  
Rating Scale ◽  
Test Results ◽  
Cognitive Dysfunctions ◽  
Severity Of Depression ◽  
Primary Male ◽  
Student’S T ◽  
The Relationship ◽  
Degrees Of Severity ◽  
Student’S T Test

Background/Aim. The relationship between alcoholism and depression is observed in clinical trials. The factors which could predict persistence of secondary depression after alcohol withdrawal are not enough explored on admission. The differences between depressed (DA) and non-depressed (NDA) alcoholics regarding the degrees of severity of withdrawal, severity of depression and the intensity of cognitive dysfunctions were explored on admission to investigate possibility of prediction of the development of secondary depression in alcoholics. Methods. A group of primary male alcoholics (n=86) was recruited during inpatient treatment. After 4 weeks alcoholics were divided in the DA group (n=43) and NDA (n=43) group according to the score on the Hamilton Depression Rating Scale (HAM-D). Clinical assessment of withdrawal, scoring on the Alcohol Dependency Severity Scale- ASD, and scoring on the Mini Mental Scale-MMSE were performed in all the participants on admission. The differences between the groups were tested by the Student's t-test. Results. The DA group showed the significantly higher severity of depression, higher levels of alcohol withdrawal symptoms and cognitive dysfunctions than the NDA group on admission. Conclusion. The specific group of depressive alcoholics was shown to be characterized by the higher severity of alcoholism and depression on admission, which could predict prolonged, secondary depression. Early detection and concurrent therapy of secondary depression could improve the treatment, and reduce the relapse of alcoholism.

scholarly journals Sports potential modeling of young basketball players: a preliminary analysis

2019 ◽  
Vol 21 ◽  
Author(s):  
Dilson Borges Ribeiro Junior ◽  
Jeferson Macedo Vianna ◽  
André de Assis Lauria ◽  
Emerson Filipino Coelho ◽  
Francisco Zacaron Werneck
Keyword(s):  
Adult Height ◽  
High Potential ◽  
Basketball Players ◽  
Chi Square ◽  
Chi Square Test ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test ◽  
Adult Stature

Abstract The aims of this study were: 1) to evaluate the sports potential of young basketball players; 2) to identify variables that discriminate sports potential assessed by coaches; 3) to verifythe relationship between classification of the multidimensional profile of athletes and classification of the sports potential by coaches. Sixty-two young basketball players aged 15.6±1.1 years from U-15 (n = 24) and U-17 (n = 38) categories participated in the study. A test battery was applied to evaluate sports potential indicators: 1) anthropometric; 2) physicomotor; 3) psychological;4) skills;5) socio-environmental;6) maturational and 7) sports potential.Clusteranalysis was performed in three groups: high, medium and low potential. Student’s t-test was used for the comparison between athletes evaluated by the coach as excellent and the others and the Chi-Square test to verify the relationship between sports potential classifications. It was observed that in the high-potential group, athletes were chronologically older, with higher % predicted adult height (PMS), competitive and determined sports orientation, higher body size, lower skinfold summation, and greater physicomotor performance. In comparison with other athletes, high-potential basketball players presented higher stature, wider wingspan,longer limb length, greater predicted adult stature and higher Z score of the % PMS. It could be concluded that the multidimensional approach was useful for the evaluation of the sports potential of young basketball players, requiring the use of multidimensional variables, in addition to coaches’ opinion regarding the potential of their athletes.

scholarly journals Clarifying the two facets of Self-Oriented Perfectionism: influences on affect and the Big Five traits of personality in children

2019 ◽  
Vol 35 (2) ◽  
pp. 280-289
Author(s):  
María Vicent ◽  
Cándido J. Inglés ◽  
Ricardo Sanmartín ◽  
Carolina Gonzálvez ◽  
María del Pilar Aparicio-Flores ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Negative Affect ◽  
Positive Affect ◽  
Big Five ◽  
Openness To Experience ◽  
Effect Sizes ◽  
Big Five Traits ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test

This study analyses the relationship between the perfectionism dimensions, i.e. Self-Oriented Perfectionism-Critical (SOP-C) and Self-Oriented Perfectionism-Striving (SOP-S), and affect and the Big Five traits of personality in a sample of 804 Spanish students aged 8 to 11 (M  = 9.57; DE = 1.12). Student’s t test, Cohen’s d index and logistic regression analysis were used. The high SOP-C group scored significantly higher than their peers having low SOP-C on Negative Affect and Neuroticism, and lower on Positive Affect, Agreeableness, Consciousness and Openness to Experience. To the contrary, students with high SOP-S scored significantly higher on all adaptive dimensions (i.e. Positive Affect, Extraversion, Agreeableness, Consciousness and Openness to Experience), and lower on Negative Affect and Neuroticism. Effect sizes were small for most of statistically significant differences. These findings were also supported by regression analysis. Results are discussed in light of the debate on the adaptive or maladaptive nature of Self-Oriented Perfectionism.

Paricalcitol and Peritoneal Protein Loss in Peritoneal Dialysis: A Double-Center Study

2018 ◽  
Vol 46 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Teresa Jerónimo ◽  
Anabela Malho Guedes ◽  
Gloria del Peso ◽  
Ana Paula Silva ◽  
Rafael Selgas ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Multivariate Analysis ◽  
Peritoneal Dialysis ◽  
Pearson Correlation ◽  
Pearson Correlation Coefficient ◽  
Protein Loss ◽  
Student’S T ◽  
The Relationship ◽  
Center Study ◽  
Student’S T Test

Background/Aims: Peritoneal protein loss (PPL) is associated with cardiovascular disease and mortality in peritoneal dialysis (PD). Controversial results have been published about the effect of paricalcitol in PPL among PD patients. This study intends to analyze the relationship between paricalcitol and PPL in PD. Methods: In a retrospective study, prevalent PD patients were divided into 2 groups: “with paricalcitol” and “without paricalcitol”. X2-test, Student’s t test, Pearson correlation coefficient and Logistic Regression analysis were applied. Results: Eighty-two patients were included. PPL was lower among patients medicated with paricalcitol (5.17 ± 1.71 vs. 6.79 ± 2.10 g/24 h, p = 0.0001). In multivariate analysis, paricalcitol and dialysate/plasma ratio of creatinine (D/P creatinine) were independently related to PPL (OR 4.270 [1.437–12.684], p = 0.009 and OR 0.205 [0.064–0.659], p = 0.008, respectively), adjusted for diabetes. Conclusion: Paricalcitol and D/P creatinine were independently related to PPL. Paricalcitol may have an effect on PPL in PD patients

scholarly journals Food Markets: A Motivation-Based Segmentation of Tourists

2020 ◽  
Vol 17 (7) ◽  
pp. 2312 ◽  
Author(s):  
Ana Mᵃ Castillo-Canalejo ◽  
Sandra Mᵃ Sánchez-Cañizares ◽  
Luna Santos-Roldán ◽  
Guzmán Antonio Muñoz-Fernández
Keyword(s):  
Cluster Analysis ◽  
Food Markets ◽  
Economic Agents ◽  
Tourism Management ◽  
Branding Strategies ◽  
Student’S T ◽  
Relationship Of ◽  
The Relationship ◽  
New Strategies ◽  
Student’S T Test

Food markets are becoming popular as new spaces for recreation, and this research aims to discover the motivations driving the tourists that visit these markets. Factorial analysis, cluster analysis and Student’s t-test were applied on 456 surveys from two food markets in Córdoba (Spain). Three motivational factors were obtained: Gastronomic experience and novelty; hedonism and leisure; and the relationship of the experience with work. Segmenting and analyzing the profile of the tourist may help economic agents develop new strategies for the tourism management of a destination and more accurate marketing and branding strategies that target specific customers with a niche message. The study could help develop products that align with tourists’ motives to increase satisfaction and loyalty.

scholarly journals Empathy and Personality Styles in Medical Students

2020 ◽  
Vol 29 (2) ◽  
pp. 73-87
Author(s):  
Yolanda Dávila Pontón ◽  
Alejandro Reyes Reyes ◽  
Aracelis Calzadilla Núñez ◽  
Víctor Patricio Díaz Narváez ◽  
Robert Utsman ◽  
...  
Keyword(s):  
Medical Students ◽  
Educational Level ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Personality Styles ◽  
Empathy Scale ◽  
Mean Differences ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test

This study aimed to establish the relationship between empathy and personality styles in medical students, considering the differences by gender. The participants were 278 students of the medical career of the Universidad del Azuay, Ecuador. They were evaluated using the Jefferson empathy scale and the Millon Index of Personality Styles. Relationships between empathy and personality styles were examined using Pearson's correlation coefficient and hierarchical multiple linear regression analysis, for comparisons by gender and educational levels; with both Student's t test and analysis of variance used respectively. Results indicated that the factor structure of the empathy scale is invariant between men and women, noticing gender differences in care with compassion and total empathy, with women presenting a higher mean. Differences are observed by educational level, where the general empathy in the first three years grows progressively, and then slightly decrease. In conclusion,  female students present a mean score of total empathy greater than men, with differences of empathy according to educational level

Main bronchial diverticula in the subcarinal region: Their relation to airflow limitations

2012 ◽  
Vol 53 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Takeshi Higuchi ◽  
Naoya Takahashi ◽  
Motoi Shiotani ◽  
Suguru Sato ◽  
Atsushi Ohta ◽  
...  
Keyword(s):  
Thin Section ◽  
Pathological Condition ◽  
Chest Ct ◽  
Pulmonary Diseases ◽  
Chronic Obstructive ◽  
Study Group ◽  
Obstructive Pulmonary Disease ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test

Background To date, bronchial diverticula have generally been treated as a pathological condition associated with chronic obstructive pulmonary disease (COPD), although only a limited amount of published information is available on the relationship between bronchial diverticula as depicted by multidetector computed tomography (MDCT) and airflow limitations. Purpose To evaluate the relationship between airflow limitations and main bronchial diverticula in the subcarinal region using spirometry and thin-section MDCT. Material and Methods A total of 189 consecutive adult patients were retrospectively evaluated based on spirometry and thin-section MDCT of the chest. All examinations were performed at our institution between June and October 2008. The study group included 70 women and 119 men with a mean age of 65 years (range 19–86 years). The relationship between the FEV1% and bronchial diverticula in the subcarinal region was analyzed (Student's t-test). Results The indications for conducting the examinations were pulmonary diseases (82 patients), cardiovascular diseases (22), extrapulmonary malignancies (74), and other conditions (11). A total of 84/189 (44.4%) patients showed bronchial diverticula, and the FEV1% of 70/84 (83.3%) patients was above 70. The FEV1% of patients with lesions ranged from 26.0 to 97.8 (mean 76.8), whereas the range was 28.1–94.4 (mean 73.7) in those without lesions. There was no significant association between the FEV1% and the presence of subcarinal bronchial diverticula ( P > 0.05). Conclusion Our data demonstrate that thin-section chest CT commonly demonstrates main bronchial diverticula in the subcarinal region in patients without airflow limitations. We propose that the presence of a small number of tiny bronchial diverticula under the carina may not be a criterion for the diagnosis of COPD.

Relación entre rendimiento académico, actividad física y consumo de alcohol y tabaco en una población Universitaria

2019 ◽  
pp. 10-16
Author(s):  
Zoila Gómez-Cruz ◽  
Patricia Landeros-Ramírez ◽  
Alfonsina Núñez-Hernández ◽  
Cecilia Jiménez-Plascencia
Keyword(s):  
Physical Activity ◽  
Academic Performance ◽  
Tobacco Consumption ◽  
Essential Factor ◽  
University Center ◽  
Chi Squared ◽  
Student’S T ◽  
The University ◽  
The Relationship ◽  
Student’S T Test

The student’s academic performance is an essential factor indicator. There are several factors that could influence on such performance, so the objective of this work was to analyze the relationship between the academic performance and different factors such as physical activity, alcohol and tobacco consumption in students of the University Center of Biological and Agricultural Sciences (CUCBA) of the Universidad de Guadalajara (UdeG). To this aim, 200 both genders students were asked to consent to apply an inquiry: The academic performance was classified into three levels: Excellent / Very Good (90-100), Good (80-89) and Regular / Bad (<80). The academic status was determined and grouped into four categories: graduates, not graduates, active and irregular. The results were analyzed by Mean Test, Standard deviation, Student's t-test and Chi-squared test. 41% of the enrolled subjects were women and 59% men. The results showed that smoking students had a lower academic performance (p <0.05) than non-smokers, however, in the present study it was not found a significant relationship between alcohol consumption or physical activity and academic performance. It is intended to contribute with proposals tending to strengthen healthy lifestyles and to improve the educacional indicators of this university community.

Condylar Asymmetry Measurements in Patients with Temporomandibular Disorders

2004 ◽  
Vol 5 (3) ◽  
pp. 59-65 ◽  
Author(s):  
Ali Alp Sağlam ◽  
Gülperi Şanli
Keyword(s):  
Temporomandibular Disorders ◽  
Asymmetry Index ◽  
T Test ◽  
Control Group ◽  
The Mean ◽  
Student’S T ◽  
The Relationship ◽  
Experimental Group ◽  
Student’S T Test

Abstract Objectives The relationship between condylar asymmetry and handedness of the patients with temporomandibular disorders (TMD) and patients with no signs or symptoms of TMD was investigated. The experimental group consisted of 25 patients aged 15 to 52 years who were referred for treatment of TMD. The mean age of this group was 26.24 years. The control group consisted of 25 patients aged 14 to 52 years (mean age: 26.16 years). Methods The formula by Habets et al.14 was used to express the symmetry between the condyles and the rami on the orthopantomogram (OPG) image. Differences between bothgroups and subgroups (condyle, ramus, condyle plus ramus) regarding symmetry were calculated with the Student's t-test. Results The mean of condylar asymmetry was found to be 11.11 ± 11.03% in the TMD group. However, in the control group, the mean of condylar asymmetry was found to be 8.36 ± 6.27%. No statistically significant differences were found between condylar asymmetry in both groups (p>0.05). Conclusions No statistically significant differences were found between condylar asymmetry index in patients with TMD according to myogenous problems and in patients with no signs or symptoms of TMD. Citation Sağlam AA, Şanli G. Condylar Asymmetry Measurements in Patients with Temporomandibular Disorders. J Contemp Dent Pract 2004 August;(5)3:059-065.

scholarly journals Relationship between children’s and parents’ blood pressure

2014 ◽  
Vol 54 (4) ◽  
pp. 202
Author(s):  
Desy Aswira Nasution ◽  
Rusdidjas Rusdidjas ◽  
Supriatmo Supriatmo ◽  
Rafita Ramayati ◽  
Oke Rina Ramayani ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Numerical Data ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Arterial Blood ◽  
History Of ◽  
Family History Of Hypertension ◽  
Student’S T ◽  
The Relationship ◽  
Student’S T Test

Background A family history of hypertension is a risk factor forhypertension in children. Past studies have reported a significantrelationship between elevated blood pressure in children andhypertensive parents.Objective To assess for an association between blood pressure inchildren and that of their parents.Methods A cross-sectional study was conducted in 90 childrenaged 6-18 years in Baringin Village, Panyabungan, from May toJune 2010. Subjects were collected by consecutive sampling.Classification of hypertension was based on Fourth Task ForceGuidelines by measuring blood pressure, height, and weight. Weused Student's T-test to analyze numerical data. Simple linearregression was used to investigate the relationship between bloodpressures of children and their parents.Results Of the 90 participants recruited, 24 boys and 17 girlshad hypertensive parents. The mean systolic (SBP) , diastolic(DBP) and arterial blood pressure (MABP) were significantlyhigher in children with hyperten sive parents than in childrenwith normotensive parents [ (SBP 116. 7 (SD 7 .07) vs. 87 .1 (SD13.57) mmHg; P=0.0001), (DBP 77.8 (SD 8.33) vs. 51.8 (SD11.70) mmHg; P=0.0001), (MABP 90.7 (SD 7.41) vs . 63 .6(12.10) mmHg; P=0.000 1] . There was a significant relationshipbetween elevated SBP in boys and their fathers, as indicated bythe correlation coefficient (r =0.806; P=0.0001).Conclusion The blood pressure is significantly higher in childrenwith hypertensive parents than in those with normotensiveparents. There is a correlation between SBP in boys and that oftheir fathers.

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