Pub Date : 2017-06-25DOI: 10.4172/2155-6180.1000353
S. Banik, Golam Kibria Bm
Correlation measures the strength of association between two variables, which plays an important role in various fields, such as Health Science, Economics, Finance, Engineering, Environmental science among others. Several tests for testing the population correlation coefficient are proposed in a literature by various researchers at different time points. This paper evaluates the performance of some of the prominent test statistics for testing the population correlation coefficient based on empirical size and power of the tests. Some bivariate distributions, such as normal, lognormal, gamma and chi-square are considered to compare the performance of the test statistics. We believe that the findings of this paper will make an important contribution to select some good test statistics to find the relationship between two variables.
{"title":"Size and Power Properties of Some Test Statistics for Testing thePopulation Correlation Coefficient Ï","authors":"S. Banik, Golam Kibria Bm","doi":"10.4172/2155-6180.1000353","DOIUrl":"https://doi.org/10.4172/2155-6180.1000353","url":null,"abstract":"Correlation measures the strength of association between two variables, which plays an important role in various fields, such as Health Science, Economics, Finance, Engineering, Environmental science among others. Several tests for testing the population correlation coefficient are proposed in a literature by various researchers at different time points. This paper evaluates the performance of some of the prominent test statistics for testing the population correlation coefficient based on empirical size and power of the tests. Some bivariate distributions, such as normal, lognormal, gamma and chi-square are considered to compare the performance of the test statistics. We believe that the findings of this paper will make an important contribution to select some good test statistics to find the relationship between two variables.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000353","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45968579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-31DOI: 10.4172/2155-6180.1000350
Zaixing Li
Mixed model/mixed modeling [1,2] is an important area/tool in statistics. It includes fixed effects and random effects. In fact, random effects (mixed) models were introduced by Fisher [3] where the correlations of trait values between relatives were studied. One-way analysis of variance (ANOVA) model and two way ANOVA are two ordinary and widely-used mixed models. Now two kinds of mixed models are mainly mentioned in literatures. One is to model clustered data/repeated data/longitudinal data [4] where the response may be divided into independent sub-vectors and the covariance matrix of random effects is very general, the other is similar to the two-way ANOVA model and some is to act as a representation tool for the nonparametric function [5,6] where the response may not be divided into independent sub-vectors and the covariance matrix of random effects is usually with special structures.
{"title":"A Review on Mixed Models","authors":"Zaixing Li","doi":"10.4172/2155-6180.1000350","DOIUrl":"https://doi.org/10.4172/2155-6180.1000350","url":null,"abstract":"Mixed model/mixed modeling [1,2] is an important area/tool in statistics. It includes fixed effects and random effects. In fact, random effects (mixed) models were introduced by Fisher [3] where the correlations of trait values between relatives were studied. One-way analysis of variance (ANOVA) model and two way ANOVA are two ordinary and widely-used mixed models. Now two kinds of mixed models are mainly mentioned in literatures. One is to model clustered data/repeated data/longitudinal data [4] where the response may be divided into independent sub-vectors and the covariance matrix of random effects is very general, the other is similar to the two-way ANOVA model and some is to act as a representation tool for the nonparametric function [5,6] where the response may not be divided into independent sub-vectors and the covariance matrix of random effects is usually with special structures.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45219887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-31DOI: 10.4172/2155-6180.1000348
Ashfaq Ali, M. Ahmad, Z. Iqbal, A. Basit
In this study, significant risk factors of Helicobacter pylori infection in Lahore are investigated through a case-control study by using descriptive and analytical approaches. A sample of 362 subjects was selected from the Gastroenterology Departments and OPDs of different hospitals of Lahore. About 25 risk factors with sub categories were included in the study. For bivariate analysis, the chi-square, phi/v statistics and Kendall’s tau-b are used. From descriptive analysis, it was found that the persons who eat from restaurants have more risk of infection as compare to persons who eat homemade food. By the descriptive analysis, it was also observed that risk of Helicobacter pylori infection increases with an increase in the number of family members per house and in the number of persons living per room. Furthermore, similar results were observed in the bivariate analysis. In the analysis, the five risk factors including age, food eat, food liked, dental complains and number of persons living per room are found to be positively significant having the odds ratios and 95% confidence intervals of odds ratios (1.025; 1.003-1.047), (9.596; 4.767-19.314), (3.500; 1.509-8.119), (3.204; 1.685-6.094) and (2.772; 1.496-5.139), respectively. While the three risk factors including usage of tea, educational level and sewerage system are found to be negatively significant having odds ratios and 95% confidence intervals for the odds ratios (0.221; 0.119-0.411), (0.216; 0.115-0.404) and (0.401; 0.218-0.738), respectively, which indicates that these three risk factors are protective factors against Helicobacter pylori infection. According to this study, the subjects who eat from restaurants have higher risk of Helicobacter pylori infection as compared to all other risk factors.
{"title":"Identification of the Risk Factors Associated with Helicobacter pyloriInfection in Lahore, Pakistan","authors":"Ashfaq Ali, M. Ahmad, Z. Iqbal, A. Basit","doi":"10.4172/2155-6180.1000348","DOIUrl":"https://doi.org/10.4172/2155-6180.1000348","url":null,"abstract":"In this study, significant risk factors of Helicobacter pylori infection in Lahore are investigated through a case-control study by using descriptive and analytical approaches. A sample of 362 subjects was selected from the Gastroenterology Departments and OPDs of different hospitals of Lahore. About 25 risk factors with sub categories were included in the study. For bivariate analysis, the chi-square, phi/v statistics and Kendall’s tau-b are used. From descriptive analysis, it was found that the persons who eat from restaurants have more risk of infection as compare to persons who eat homemade food. By the descriptive analysis, it was also observed that risk of Helicobacter pylori infection increases with an increase in the number of family members per house and in the number of persons living per room. Furthermore, similar results were observed in the bivariate analysis. In the analysis, the five risk factors including age, food eat, food liked, dental complains and number of persons living per room are found to be positively significant having the odds ratios and 95% confidence intervals of odds ratios (1.025; 1.003-1.047), (9.596; 4.767-19.314), (3.500; 1.509-8.119), (3.204; 1.685-6.094) and (2.772; 1.496-5.139), respectively. While the three risk factors including usage of tea, educational level and sewerage system are found to be negatively significant having odds ratios and 95% confidence intervals for the odds ratios (0.221; 0.119-0.411), (0.216; 0.115-0.404) and (0.401; 0.218-0.738), respectively, which indicates that these three risk factors are protective factors against Helicobacter pylori infection. According to this study, the subjects who eat from restaurants have higher risk of Helicobacter pylori infection as compared to all other risk factors.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2017-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48383770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-31DOI: 10.4172/2155-6180.1000351
Koech Jk, Mutiso Mj, Koskei Jk
One of the major concerns among developing countries in recent decades is the effect of declining food security with ever-growing population. Hence, the importance of adopting cost effective farming methods has led to the development of various statistical methods to alleviate food insecurity. Among these methods, CCD has gained significant attention to its application in agriculture. In this paper, the response surface methodology (RSM) was applied in order to determine the effects of the factors potassium (K), nitrogen (N) and phosphorus (P) on the yield of potato tuber. The predicted values for the yield of potato tuber by the response functions were in a very close agreement with experimental data (R2=90%). The second-order model was developed by solving the parameters of the regression equation using the method of least squares. The optimal combinations of the factors potassium (K), nitrogen (N) and phosphorus (P) with yield as the response of interest were determined by analyzing the 3D response surface plots and using the method of steepest ascent. Using ridge analysis method which corresponds to the method of steepest ascent, the optimal yield of potato tuber was estimated to be 29.26 t ha-1 which is much higher than the current national target of 14 t ha-1 with optimum factor levels being K=35.36 kg K2o ha-1, N=78.71 Kg N ha-1 and P=160.69 Kg P=160.69 kg P2o5ha-1, respectively. Nitrogen and phosphorous had a significant positive linear effects on the potato tuber yield. Based on the results, it can be concluded that the response surface methodology is a suitable approach for determining the optimal conditions of the selected fertilizer types.
近几十年来，发展中国家主要关注的问题之一是人口不断增长导致粮食安全下降的影响。因此，采用具有成本效益的耕作方法的重要性导致了各种统计方法的发展，以减轻粮食不安全。其中，CCD技术在农业上的应用受到了广泛的关注。采用响应面法(RSM)研究了钾(K)、氮(N)、磷(P)对马铃薯块茎产量的影响。利用响应函数对马铃薯块茎产量的预测值与实验数据非常吻合(R2=90%)。利用最小二乘法对回归方程的参数进行求解，建立了二阶模型。通过三维响应面分析，采用最陡爬坡法确定了以产量为目标响应的钾、氮、磷因子的最佳组合。采用与最陡爬坡法相对应的脊分析法，估算马铃薯块茎的最佳产量为29.26 t ha-1，远高于目前国家目标14 t ha-1，最佳因子水平分别为K=35.36 kg K2o ha-1、N=78.71 kg N ha-1和P=160.69 kg P2o5ha-1。氮磷对马铃薯块茎产量有显著的正线性影响。结果表明，响应面法是确定所选肥料类型最优条件的一种合适的方法。
{"title":"Response Surface Methodology Approach to the Optimization of Potato(Solanum tuberosum) Tuber Yield Using Second-Order Rotatable Design","authors":"Koech Jk, Mutiso Mj, Koskei Jk","doi":"10.4172/2155-6180.1000351","DOIUrl":"https://doi.org/10.4172/2155-6180.1000351","url":null,"abstract":"One of the major concerns among developing countries in recent decades is the effect of declining food security with ever-growing population. Hence, the importance of adopting cost effective farming methods has led to the development of various statistical methods to alleviate food insecurity. Among these methods, CCD has gained significant attention to its application in agriculture. In this paper, the response surface methodology (RSM) was applied in order to determine the effects of the factors potassium (K), nitrogen (N) and phosphorus (P) on the yield of potato tuber. The predicted values for the yield of potato tuber by the response functions were in a very close agreement with experimental data (R2=90%). The second-order model was developed by solving the parameters of the regression equation using the method of least squares. The optimal combinations of the factors potassium (K), nitrogen (N) and phosphorus (P) with yield as the response of interest were determined by analyzing the 3D response surface plots and using the method of steepest ascent. Using ridge analysis method which corresponds to the method of steepest ascent, the optimal yield of potato tuber was estimated to be 29.26 t ha-1 which is much higher than the current national target of 14 t ha-1 with optimum factor levels being K=35.36 kg K2o ha-1, N=78.71 Kg N ha-1 and P=160.69 Kg P=160.69 kg P2o5ha-1, respectively. Nitrogen and phosphorous had a significant positive linear effects on the potato tuber yield. Based on the results, it can be concluded that the response surface methodology is a suitable approach for determining the optimal conditions of the selected fertilizer types.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000351","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44468694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-31DOI: 10.4172/2155-6180.1000349
Senol Dogan
Aim of study: Leukemia has different subtypes, which present unique clinical and molecular characteristics. MLL (Mixed Lineage Leukemia) is one of the new different subtypes than AML and ALL. Materials and Methods: Genomic characterization is the main key understanding the differences of MLL by analysis of differential gene expression, methylation patterns and mutational spectra that were compared and analyzed between MLL and AML types (n=197). Results: According to the genomic characterization of MLL, differentially expressed 114 genes were selected and 37 of them targeted genes having more than 2 fold expression change, including HOXA9, CFH, DDX4, MSH4, MSMB, TWIST1, ZSWIM2, POU6F2. To measure the aberrant methylation is the second genomic characterization of this research because the rearrangements of MLL gene leading to aberrant methylation. The methylation data were compared between cancer and control, so high methylated genes have been detected between MLL and AML types. The methylation loci were categorized into two groups: ≥ 10 fold difference and ≥ 5 and ≤ 10 fold difference. Some of the genes high methylated more than one location such as; RAET1E, HSD17B2, RNASE11, DGK1, POU6F2, NAGS, PIK3C2G, GADL1, and KRT13. In addition to that, analysis of somatic mutation gives us that CFH has the highest point mutation 9,92%. Conclusion: Overall, the MLL genomic characterization shows that it is different than AML and exhibits a unique molecular and biological phenotype and point to new possible targetable genes for future treatment of MLL leukemia are two important values.
{"title":"New Possible Targetable Genes for Future Treatment of Mixed Lineage Leukemia","authors":"Senol Dogan","doi":"10.4172/2155-6180.1000349","DOIUrl":"https://doi.org/10.4172/2155-6180.1000349","url":null,"abstract":"Aim of study: Leukemia has different subtypes, which present unique clinical and molecular characteristics. MLL (Mixed Lineage Leukemia) is one of the new different subtypes than AML and ALL. Materials and Methods: Genomic characterization is the main key understanding the differences of MLL by analysis of differential gene expression, methylation patterns and mutational spectra that were compared and analyzed between MLL and AML types (n=197). Results: According to the genomic characterization of MLL, differentially expressed 114 genes were selected and 37 of them targeted genes having more than 2 fold expression change, including HOXA9, CFH, DDX4, MSH4, MSMB, TWIST1, ZSWIM2, POU6F2. To measure the aberrant methylation is the second genomic characterization of this research because the rearrangements of MLL gene leading to aberrant methylation. The methylation data were compared between cancer and control, so high methylated genes have been detected between MLL and AML types. The methylation loci were categorized into two groups: ≥ 10 fold difference and ≥ 5 and ≤ 10 fold difference. Some of the genes high methylated more than one location such as; RAET1E, HSD17B2, RNASE11, DGK1, POU6F2, NAGS, PIK3C2G, GADL1, and KRT13. In addition to that, analysis of somatic mutation gives us that CFH has the highest point mutation 9,92%. Conclusion: Overall, the MLL genomic characterization shows that it is different than AML and exhibits a unique molecular and biological phenotype and point to new possible targetable genes for future treatment of MLL leukemia are two important values.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49054504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-28DOI: 10.4172/2155-6180.1000344
M. Kaewbumrung, B. Wiwatanapataphee, S. Orankitjaroen, T. Siriapisith
In this paper, we propose a mathematical model of turbulence flow of fluid through a deformable channel to study the pulsatile blood flow in the coronary system with arterial stenosis. Blood is assumed to be an incompressible non- Newtonian fluid and its motion is considered as turbulent and modelled by the mass and momentum conservations with turbulent mixing energy and specific dissipation rate. The mechanical deformation of the arterial wall is modelled by a hyperelastic differential equation. The pulsatile behaviour during each heartbeat is assigned on the entrance and exit boundaries. Numerical simulation based on the Finite Element method for the solution of arterial wall deformation, and the Arbitrary Lagrangian Eulerian Finite Volume method for the turbulence fluid-flow solution is used to investigate the effect of stenosis severity at the proximal part of the left anterior descending artery on the blood velocity, the pressure distribution and the wall shear stresses along the flow direction.
{"title":"Numerical Simulation of Turbulent Blood Flow in the System of CoronaryArteries with Stenosis","authors":"M. Kaewbumrung, B. Wiwatanapataphee, S. Orankitjaroen, T. Siriapisith","doi":"10.4172/2155-6180.1000344","DOIUrl":"https://doi.org/10.4172/2155-6180.1000344","url":null,"abstract":"In this paper, we propose a mathematical model of turbulence flow of fluid through a deformable channel to study the pulsatile blood flow in the coronary system with arterial stenosis. Blood is assumed to be an incompressible non- Newtonian fluid and its motion is considered as turbulent and modelled by the mass and momentum conservations with turbulent mixing energy and specific dissipation rate. The mechanical deformation of the arterial wall is modelled by a hyperelastic differential equation. The pulsatile behaviour during each heartbeat is assigned on the entrance and exit boundaries. Numerical simulation based on the Finite Element method for the solution of arterial wall deformation, and the Arbitrary Lagrangian Eulerian Finite Volume method for the turbulence fluid-flow solution is used to investigate the effect of stenosis severity at the proximal part of the left anterior descending artery on the blood velocity, the pressure distribution and the wall shear stresses along the flow direction.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":"8 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2017-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000344","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43100770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-28DOI: 10.4172/2155-6180.1000347
Senol Dogan, N. Nalcaci, S. Doğan, A. Badnjević, A. Kurtovic, D. Marjanovic
Stress is a part of human life, especially for urban citizens. Stress is inseparable characteristics of student life, especially exam days. Stress management is one of the first steps which can affect students success during the exams, especially in universities. Blood pressure is the first stress observation symptom to understand its level. Therefore, to understand the stress impact of university students during the exam weeks, a conditional experiment has been designed. 200 students were selected from Bosnian and Turkish female and male. The students` blood systolic, diastolic and heart rate were measured to detect the differences between non-exams days and exam days. The blood pressure measurement has been done 3 times in specific times, non-exam days, midterm and final days. Since non-exam days were taken as stress off days, they were supposed that these days were control data to compare with exam days to see the differences. As a result of the measurements, Bosnian females showed the highest increasing, systolic 13.2%, diastolic 9.3% and heart rate 8.5% during the midterm exam days. The group has been followed by Bosnian males, systolic 6.9%, diastolic 6.1% and heart rate 6.63 increased during the midterm days. Although Turkish students blood pressure and heart rate increased, the values were less than Bosnian students. Moreover, high correlation significance results belonged to Bosnian females and males, 0.722 and 0.698 respectively. Finally, it was concluded that if students have scholarship they have more blood pressure during the exams. While 95% of Bosnian females and 90% of Bosnian males have some scholarship, no Turkish students have scholarship demonstrated the differences between Bosnian and Turkish students blood measurements.
{"title":"Changes in Blood Pressure and Heart Rate Measurement UndergraduateStudents During Exam Period","authors":"Senol Dogan, N. Nalcaci, S. Doğan, A. Badnjević, A. Kurtovic, D. Marjanovic","doi":"10.4172/2155-6180.1000347","DOIUrl":"https://doi.org/10.4172/2155-6180.1000347","url":null,"abstract":"Stress is a part of human life, especially for urban citizens. Stress is inseparable characteristics of student life, especially exam days. Stress management is one of the first steps which can affect students success during the exams, especially in universities. Blood pressure is the first stress observation symptom to understand its level. Therefore, to understand the stress impact of university students during the exam weeks, a conditional experiment has been designed. 200 students were selected from Bosnian and Turkish female and male. The students` blood systolic, diastolic and heart rate were measured to detect the differences between non-exams days and exam days. The blood pressure measurement has been done 3 times in specific times, non-exam days, midterm and final days. Since non-exam days were taken as stress off days, they were supposed that these days were control data to compare with exam days to see the differences. As a result of the measurements, Bosnian females showed the highest increasing, systolic 13.2%, diastolic 9.3% and heart rate 8.5% during the midterm exam days. The group has been followed by Bosnian males, systolic 6.9%, diastolic 6.1% and heart rate 6.63 increased during the midterm days. Although Turkish students blood pressure and heart rate increased, the values were less than Bosnian students. Moreover, high correlation significance results belonged to Bosnian females and males, 0.722 and 0.698 respectively. Finally, it was concluded that if students have scholarship they have more blood pressure during the exams. While 95% of Bosnian females and 90% of Bosnian males have some scholarship, no Turkish students have scholarship demonstrated the differences between Bosnian and Turkish students blood measurements.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2017-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000347","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43758805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-28DOI: 10.4172/2155-6180.1000346
Fang Yang, X. Niu, Jianchang Lin
Polychotomous response models are commonly used in the clinical trials to analyze categorical or ordinal response data. Motivated by investigating of relationship between BMI categories and several risk factors, we carry out the application studies to examine the impact of risk factors on BMI categories, especially for categories of “Overweight” and “Obesities”. In this study, we apply the Bayesian methodology through a mixed-effects polychotomous response model to the Diverse Population Collaboration (DPC) dataset. Using the mixed-effects Bayesian polychotomous response model with uniform improper priors, we would get similar interpretations of the association between risk factors and BMI, which are in great agreement with the results documented in literature. Our application showed that the Bayesian mixed-effects polychotomous response model with improper priors is a very useful statistical technique for solving real word problems.
{"title":"Bayesian Mixed-effects Polychotomous Response Model with Applicationto Diverse Population Collaboration (DPC) Data","authors":"Fang Yang, X. Niu, Jianchang Lin","doi":"10.4172/2155-6180.1000346","DOIUrl":"https://doi.org/10.4172/2155-6180.1000346","url":null,"abstract":"Polychotomous response models are commonly used in the clinical trials to analyze categorical or ordinal response data. Motivated by investigating of relationship between BMI categories and several risk factors, we carry out the application studies to examine the impact of risk factors on BMI categories, especially for categories of “Overweight” and “Obesities”. In this study, we apply the Bayesian methodology through a mixed-effects polychotomous response model to the Diverse Population Collaboration (DPC) dataset. Using the mixed-effects Bayesian polychotomous response model with uniform improper priors, we would get similar interpretations of the association between risk factors and BMI, which are in great agreement with the results documented in literature. Our application showed that the Bayesian mixed-effects polychotomous response model with improper priors is a very useful statistical technique for solving real word problems.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000346","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47642719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-28DOI: 10.4172/2155-6180.1000343
I. Dialsingh, Sherwin P Cedeno
Advances in Genomics have re-energized interest in multiple hypothesis testing procedures but have simultaneously created new methodological and computational challenges. In Genomics for instance, it is now commonplace for experiments to measure expression levels in thousands of genes creating large multiplicity problems when thousands of hypotheses are to be tested simultaneously. Within this context we seek to identify differentially expressed genes, that is, genes whose expression levels are associated with a particular response or covariate of interest. The False Discovery Rate (FDR) is the preferred measure since the Family Wise Error Rates (FWERs) are usually overly restrictive. In the FDR methods, estimation of the proportion of null hypotheses (π0) is an important parameter that needs to be estimated. In this paper, we compare the effectiveness of 12 methods for estimating π0 when the test statistics are continuous using simulated data with independent, weak dependence, and moderate dependence structures.
{"title":"Comparison of Methods for Estimating the Proportion of Null HypothesesÃÂ0 in High Dimensional Data When the Test Statistics is Continuous","authors":"I. Dialsingh, Sherwin P Cedeno","doi":"10.4172/2155-6180.1000343","DOIUrl":"https://doi.org/10.4172/2155-6180.1000343","url":null,"abstract":"Advances in Genomics have re-energized interest in multiple hypothesis testing procedures but have simultaneously created new methodological and computational challenges. In Genomics for instance, it is now commonplace for experiments to measure expression levels in thousands of genes creating large multiplicity problems when thousands of hypotheses are to be tested simultaneously. Within this context we seek to identify differentially expressed genes, that is, genes whose expression levels are associated with a particular response or covariate of interest. The False Discovery Rate (FDR) is the preferred measure since the Family Wise Error Rates (FWERs) are usually overly restrictive. In the FDR methods, estimation of the proportion of null hypotheses (π0) is an important parameter that needs to be estimated. In this paper, we compare the effectiveness of 12 methods for estimating π0 when the test statistics are continuous using simulated data with independent, weak dependence, and moderate dependence structures.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000343","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43622340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-28DOI: 10.4172/2155-6180.1000345
Jason J. Z. Liao, Yifang Li, Xinhua Jiang
It is often interest of comparing two pharmacodynamics (PD) profiles in drug development. Currently the common practice is borrowing the bioequivalence (BE) rule in pharmacokinetics analysis for pharmacodynamics comparison in terms of the area under the effect curve (AUEC) of the pharmacodynamics profile. However, this may not be a feasible and sensitive enough approach since the bioequivalence approach is based on the summarized parameter of the pharmacodynamics profile rather than on directly comparison of the whole pharmacodynamics profile. In this paper, a simple but efficient and pragmatic pharmacodynamics comparability index is proposed to evaluate the comparability of pharmacodynamics profiles by comparing the whole pharmacodynamics profiles directly. Different biological products have different variability and the CV% can be in a very large range. The PD comparability index can take account of the reference knowledge into consideration in assessment but the AUEC BE type approach ignores the reference variability. The good properties of the proposed approach are illustrated through simulated data and a real dataset.
{"title":"Comparability of Pharmacodynamics Profiles with an Application to aBiosimilar Study","authors":"Jason J. Z. Liao, Yifang Li, Xinhua Jiang","doi":"10.4172/2155-6180.1000345","DOIUrl":"https://doi.org/10.4172/2155-6180.1000345","url":null,"abstract":"It is often interest of comparing two pharmacodynamics (PD) profiles in drug development. Currently the common practice is borrowing the bioequivalence (BE) rule in pharmacokinetics analysis for pharmacodynamics comparison in terms of the area under the effect curve (AUEC) of the pharmacodynamics profile. However, this may not be a feasible and sensitive enough approach since the bioequivalence approach is based on the summarized parameter of the pharmacodynamics profile rather than on directly comparison of the whole pharmacodynamics profile. In this paper, a simple but efficient and pragmatic pharmacodynamics comparability index is proposed to evaluate the comparability of pharmacodynamics profiles by comparing the whole pharmacodynamics profiles directly. Different biological products have different variability and the CV% can be in a very large range. The PD comparability index can take account of the reference knowledge into consideration in assessment but the AUEC BE type approach ignores the reference variability. The good properties of the proposed approach are illustrated through simulated data and a real dataset.","PeriodicalId":87294,"journal":{"name":"Journal of biometrics & biostatistics","volume":"8 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4172/2155-6180.1000345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47733490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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