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A Comprehensive Guide for Selecting Appropriate Statistical Tests: Understanding When to Use Parametric and Nonparametric Tests
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作者 Saed Jama Abdi 《Open Journal of Endocrine and Metabolic Diseases》 2023年第4期464-474,共11页
Choosing appropriate statistical tests is crucial but deciding which tests to use can be challenging. Different tests suit different types of data and research questions, so it is important to choose the right one. Kn... Choosing appropriate statistical tests is crucial but deciding which tests to use can be challenging. Different tests suit different types of data and research questions, so it is important to choose the right one. Knowing how to select an appropriate test can lead to more accurate results. Invalid results and misleading conclusions may be drawn from a study if an incorrect statistical test is used. Therefore, to avoid these it is essential to understand the nature of the data, the research question, and the assumptions of the tests before selecting one. This is because there are a wide variety of tests available. This paper provides a step-by-step approach to selecting the right statistical test for any study, with an explanation of when it is appropriate to use it and relevant examples of each statistical test. Furthermore, this guide provides a comprehensive overview of the assumptions of each test and what to do if these assumptions are violated. 展开更多
关键词 Statistical tests Levels of Measurement PARAMETRIC nonparametric Normal Distribution
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A Comprehensive Guide for Selecting Appropriate Statistical Tests: Understanding When to Use Parametric and Nonparametric Tests
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作者 Saed Jama Abdi 《Open Journal of Statistics》 2023年第4期464-474,共11页
Choosing appropriate statistical tests is crucial but deciding which tests to use can be challenging. Different tests suit different types of data and research questions, so it is important to choose the right one. Kn... Choosing appropriate statistical tests is crucial but deciding which tests to use can be challenging. Different tests suit different types of data and research questions, so it is important to choose the right one. Knowing how to select an appropriate test can lead to more accurate results. Invalid results and misleading conclusions may be drawn from a study if an incorrect statistical test is used. Therefore, to avoid these it is essential to understand the nature of the data, the research question, and the assumptions of the tests before selecting one. This is because there are a wide variety of tests available. This paper provides a step-by-step approach to selecting the right statistical test for any study, with an explanation of when it is appropriate to use it and relevant examples of each statistical test. Furthermore, this guide provides a comprehensive overview of the assumptions of each test and what to do if these assumptions are violated. 展开更多
关键词 Statistical tests Levels of Measurement PARAMETRIC nonparametric Normal Distribution
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New Nonparametric Rank-Based Tests for Paired Data
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作者 Guogen Shan 《Open Journal of Statistics》 2014年第7期495-503,共9页
We propose a new nonparametric test based on the rank difference between the paired sample for testing the equality of the marginal distributions from a bivariate distribution. We also consider a modification of the n... We propose a new nonparametric test based on the rank difference between the paired sample for testing the equality of the marginal distributions from a bivariate distribution. We also consider a modification of the novel nonparametric test based on the test proposed by Baumgartern, Weiβ, and Schindler (1998). An extensive numerical power comparison for various parametric and nonparametric tests was conducted under a wide range of bivariate distributions for small sample sizes. The two new nonparametric tests have comparable power to the paired t test for the data simulated from bivariate normal distributions, and are generally more powerful than the paired t test and other commonly used nonparametric tests in several important bivariate distributions. 展开更多
关键词 BWS test nonparametric test Paired DATA Power Study RANK DIFFERENCE Wilcoxon SIGNED RANK test
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Calculation of Two-Tailed Exact Probability in the Wald-Wolfowitz One-Sample Runs Test
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作者 José Moral De La Rubia 《Journal of Data Analysis and Information Processing》 2024年第1期89-114,共26页
The objectives of this paper are to demonstrate the algorithms employed by three statistical software programs (R, Real Statistics using Excel, and SPSS) for calculating the exact two-tailed probability of the Wald-Wo... The objectives of this paper are to demonstrate the algorithms employed by three statistical software programs (R, Real Statistics using Excel, and SPSS) for calculating the exact two-tailed probability of the Wald-Wolfowitz one-sample runs test for randomness, to present a novel approach for computing this probability, and to compare the four procedures by generating samples of 10 and 11 data points, varying the parameters n<sub>0</sub> (number of zeros) and n<sub>1</sub> (number of ones), as well as the number of runs. Fifty-nine samples are created to replicate the behavior of the distribution of the number of runs with 10 and 11 data points. The exact two-tailed probabilities for the four procedures were compared using Friedman’s test. Given the significant difference in central tendency, post-hoc comparisons were conducted using Conover’s test with Benjamini-Yekutielli correction. It is concluded that the procedures of Real Statistics using Excel and R exhibit some inadequacies in the calculation of the exact two-tailed probability, whereas the new proposal and the SPSS procedure are deemed more suitable. The proposed robust algorithm has a more transparent rationale than the SPSS one, albeit being somewhat more conservative. We recommend its implementation for this test and its application to others, such as the binomial and sign test. 展开更多
关键词 RANDOMNESS nonparametric test Exact Probability Small Samples QUANTILES
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Study on Key Biological Indicators of Diabetes Based on Statistical Tests
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作者 Shuaibin Yang 《Journal of Clinical and Nursing Research》 2024年第7期267-273,共7页
Normality testing is a fundamental hypothesis test in the statistical analysis of key biological indicators of diabetes.If this assumption is violated,it may cause the test results to deviate from the true value,leadi... Normality testing is a fundamental hypothesis test in the statistical analysis of key biological indicators of diabetes.If this assumption is violated,it may cause the test results to deviate from the true value,leading to incorrect inferences and conclusions,and ultimately affecting the validity and accuracy of statistical inferences.Considering this,the study designs a unified analysis scheme for different data types based on parametric statistical test methods and non-parametric test methods.The data were grouped according to sample type and divided into discrete data and continuous data.To account for differences among subgroups,the conventional chi-squared test was used for discrete data.The normal distribution is the basis of many statistical methods;if the data does not follow a normal distribution,many statistical methods will fail or produce incorrect results.Therefore,before data analysis and modeling,the data were divided into normal and non-normal groups through normality testing.For normally distributed data,parametric statistical methods were used to judge the differences between groups.For non-normal data,non-parametric tests were employed to improve the accuracy of the analysis.Statistically significant indicators were retained according to the significance index P-value of the statistical test or corresponding statistics.These indicators were then combined with relevant medical background to further explore the etiology leading to the occurrence or transformation of diabetes status. 展开更多
关键词 Diabetes diagnosis Statistical test nonparametric statistics Normality test
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A Nonparametric Model Checking Test for Functional Linear Composite Quantile Regression Models
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作者 XIA Lili DU Jiang ZHANG Zhongzhan 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2024年第4期1714-1737,共24页
This paper is focused on the goodness-of-fit test of the functional linear composite quantile regression model.A nonparametric test is proposed by using the orthogonality of the residual and its conditional expectatio... This paper is focused on the goodness-of-fit test of the functional linear composite quantile regression model.A nonparametric test is proposed by using the orthogonality of the residual and its conditional expectation under the null model.The proposed test statistic has an asymptotic standard normal distribution under the null hypothesis,and tends to infinity in probability under the alternative hypothesis,which implies the consistency of the test.Furthermore,it is proved that the test statistic converges to a normal distribution with nonzero mean under a local alternative hypothesis.Extensive simulations are reported,and the results show that the proposed test has proper sizes and is sensitive to the considered model discrepancies.The proposed methods are also applied to two real datasets. 展开更多
关键词 Composite quantile regression consistent test functional data nonparametric test quadratic form
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Nonparametric TOA estimators for low-resolution IR-UWB digital receiver 被引量:1
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作者 Yanlong Zhang Weidong Chen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第1期26-31,共6页
Nonparametric time-of-arrival(TOA) estimators for impulse radio ultra-wideband(IR-UWB) signals are proposed. Nonparametric detection is obviously useful in situations where detailed information about the statistic... Nonparametric time-of-arrival(TOA) estimators for impulse radio ultra-wideband(IR-UWB) signals are proposed. Nonparametric detection is obviously useful in situations where detailed information about the statistics of the noise is unavailable or not accurate. Such TOA estimators are obtained based on conditional statistical tests with only a symmetry distribution assumption on the noise probability density function. The nonparametric estimators are attractive choices for low-resolution IR-UWB digital receivers which can be implemented by fast comparators or high sampling rate low resolution analog-to-digital converters(ADCs),in place of high sampling rate high resolution ADCs which may not be available in practice. Simulation results demonstrate that nonparametric TOA estimators provide more effective and robust performance than typical energy detection(ED) based estimators. 展开更多
关键词 conditional test nonparametric estimator time-of-arrival(TOA) low-resolution
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A Practical Guide to Statistical Tests in the Biomedical Field: From Parametric to Nonparametric, Where and How?
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作者 Adil Gourinda Hicham El Bouri +5 位作者 Faïza Charif Zaynab Mahdi Fadila Bousgheiri Karima Sammoud Saloua Lemrabett Adil Najdi 《Journal of Biosciences and Medicines》 2024年第11期1-14,共14页
Healthcare decisions are based on scientific evidence obtained from medical studies by gathering data and analyzing it to obtain the best results. When analyzing data, biostatistics is a powerful tool, but healthcare ... Healthcare decisions are based on scientific evidence obtained from medical studies by gathering data and analyzing it to obtain the best results. When analyzing data, biostatistics is a powerful tool, but healthcare professionals lack knowledge in this field. This lack of knowledge can manifest itself in situations such as choosing the wrong statistical test for the right situation or applying a statistical test without checking its assumptions, leading to inaccurate results and misleading conclusions. With the help of this “narrative review”, the aim is to bring biostatistics closer to healthcare professionals by answering certain questions: how to describe the distribution of data? how to assess the normality of data? how to transform data? and how to choose between nonparametric and parametric tests? Through this work, our hope is that the reader will be able to choose the right test for the right situation, in order to obtain the most accurate results. 展开更多
关键词 Teaching Statistics Distribution Normality Transformation nonparametric test Parametric test
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非参数CD-CAT题库Q矩阵优化设计
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作者 黄涛 汪文义 宋丽红 《江西师范大学学报(自然科学版)》 CAS 北大核心 2024年第3期276-285,共10页
开展非参数CD-CAT题库Q矩阵的优化设计,并将它用于指导题库题目编制或选择,且它无需模型参数估计,这对于促进非参数CD-CAT进入课堂评价至关重要.受p-优化的启发,该文提出比例法生成优化Q矩阵,同时将已有的参数化模型题库设计方法推广到... 开展非参数CD-CAT题库Q矩阵的优化设计,并将它用于指导题库题目编制或选择,且它无需模型参数估计,这对于促进非参数CD-CAT进入课堂评价至关重要.受p-优化的启发,该文提出比例法生成优化Q矩阵,同时将已有的参数化模型题库设计方法推广到非参数化题库Q矩阵的优化设计.模拟研究结果显示:比例法和推广的融合法都有较好表现,而且当题库量较少时比例法更有优势. 展开更多
关键词 计算机化自适应测验 非参数选题策略 认知诊断模型 判准率 优化设计
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AVWC-test在生命科学研究中应用效果的评估 被引量:2
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作者 董长垣 陈冬娥 +2 位作者 王圣基 应时 陈晓 《中国病毒学》 CSCD 1994年第4期367-374,共8页
AVWC-tcst是新近发展起来的生物统计方法,它能把非参数资料转变成参数资料进行定量统计分析。本研究进一步从国内外刊物上公开发表的学术论文中精选出了一定数量的研究数据,用AVWC-test方法进行统计处理,并与传统... AVWC-tcst是新近发展起来的生物统计方法,它能把非参数资料转变成参数资料进行定量统计分析。本研究进一步从国内外刊物上公开发表的学术论文中精选出了一定数量的研究数据,用AVWC-test方法进行统计处理,并与传统的非参数统计方法和计量资料统计方法进行同源自身对照,研究了其统计效能。结果清楚地表明:AVWC-test方法是一种应用面广,精确、灵敏、方便的生物统计分析方法,能更好地发掘科学资料的信息,提高研究效率。 展开更多
关键词 AVWC-test 生物统计 生命科学
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Surface air temperature change in the Wuyi Mountains,southeast China
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作者 QIN Yihui WEI Yuxing +6 位作者 LU Jiayi MAO Jiahui CHEN Xingwei GAO Lu CHEN Ying LIU Meibing DENG Haijun 《Journal of Mountain Science》 SCIE CSCD 2024年第6期1992-2004,共13页
Detecting changes in surface air temperature in mid-and low-altitude mountainous regions is essential for a comprehensive understanding of warming trend with altitude.We use daily surface air temperature data from 64 ... Detecting changes in surface air temperature in mid-and low-altitude mountainous regions is essential for a comprehensive understanding of warming trend with altitude.We use daily surface air temperature data from 64 meteorological stations in Wuyi Mountains and its adjacent regions to analyze the spatio-temporal patterns of temperature change.The results show that Wuyi Mountains have experienced significant warming from 1961 to 2018.The warming trend of the mean temperature is 0.20℃/decade,the maximum temperature is 0.17℃/decade,and the minimum temperature is 0.26℃/decade.In 1961-1990,more than 63%of the stations showed a decreasing trend in annual mean temperature,mainly because the maximum temperature decreased during this period.However,in 1971-2000,1981-2010 and 1991-2018,the maximum,minimum and mean temperatures increased.The fastest increasing trend of mean temperature occurred in the southeastern coastal plains,the quickest increasing trend of maximum temperature occurred in the northwestern mountainous region,and the increase of minimum temperature occurred faster in the southeastern coastal and northwestern mountainous regions than that in the central area.Meanwhile,this study suggests that elevation does not affect warming in the Wuyi Mountains.These results are beneficial for understanding climate change in humid subtropical middle and low mountains. 展开更多
关键词 Climate change Surface air temperature Temporal and spatial changes Mann-Kendall nonparametric test Wuyi Mountains
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南昌市NDVI时空演化特征及其气候驱动因子分析
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作者 徐悦 李佳潼 +2 位作者 郭齐韵 李慧珊 吴华 《森林工程》 北大核心 2024年第5期50-61,共12页
揭示南昌市植被覆盖的演化特征和确定影响其变化趋势的主要气候驱动因子,为其长期稳定、良性发展和积极应对后续的气候变化提供指导。采用2000—2020年南昌市的NDVI月度数据、气温、降水和气压等10个气象驱动因子,利用单样本K-S(Kolmogo... 揭示南昌市植被覆盖的演化特征和确定影响其变化趋势的主要气候驱动因子,为其长期稳定、良性发展和积极应对后续的气候变化提供指导。采用2000—2020年南昌市的NDVI月度数据、气温、降水和气压等10个气象驱动因子,利用单样本K-S(Kolmogorov-Smirnov)检验、弗里德曼检验、肯德尔和谐系数检验法等非参数检验法和随机森林分析方法,对不同驱动因子的重要性进行研究。结果表明,1)在2000—2020年南昌市的NDVI呈波动下降趋势,该峰值出现在2000年,谷值则在2010年;2)城市整体植被覆盖呈现四周高中间低的空间分布规律,北部和西部地区的NDVI值相对较高且下降速率缓慢,中部的东湖区和青山湖区等NDVI值相对较低且有明显下降趋势;3)植被覆盖的极大平均值出现在每年8月,受温度的影响最显著,而风向的影响最不显著,降水的影响有一定的时滞性,植被覆盖变化应结合多要素的共同驱动作用来决定。 展开更多
关键词 归一化植被指数 非参数检验 随机森林 气候变化 驱动分析。
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改进邻域漂移的多假设检验点云降噪
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作者 时志鹏 冯肖维 赵一平 《计算机工程》 CAS CSCD 北大核心 2024年第6期276-286,共11页
在获得三维点云数据时,由于仪器、环境、算法等原因,不可避免地会使获得的点云数据带有噪声,而点云数据所携带的噪声将影响后续的点云处理效果。为了抑制三维点云数据中的噪声,同时保留其不同程度的特征,提出一种改进邻域漂移的多假设... 在获得三维点云数据时,由于仪器、环境、算法等原因,不可避免地会使获得的点云数据带有噪声,而点云数据所携带的噪声将影响后续的点云处理效果。为了抑制三维点云数据中的噪声,同时保留其不同程度的特征,提出一种改进邻域漂移的多假设点云降噪方法。首先,利用邻域点和法向双张量投票法进行特征描述;接着,利用非参数估计构建转移概率函数,并使用核回归方法对新的采样点进行权重计算,在此基础上运用粒子滤波实现邻域漂移,经过多次迭代得到非局部邻域;然后,通过多假设检验法确定不同特征点处的多个法向,并通过加权平均获得最终法向;最后,采用多假设检验的方法分别对特征点和非特征点进行滤波,产生多个候选点并使用目标函数进行优化,从而对点云模型进行降噪。利用所提方法与RIMLS、EAR、L1、PointNet方法对相同噪声模型进行恢复,并对恢复模型与原模型进行误差分析,结果表明,所提方法的平均降噪精度相比RIMLS、EAR和L1方法分别提高了38.1%、41.3%和12.4%,与PointNet相比约降低2.9%,但是所提方法无须进行数据库训练且可调参。 展开更多
关键词 点云降噪 张量投票 邻域漂移 非参数估计 核回归 多假设检验
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三峡水库干流含沙量对不同形态磷浓度的影响分析
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作者 王文静 赵旻 赵起超 《人民长江》 北大核心 2024年第10期68-76,共9页
磷是水环境质量评价和污染控制考核的重要指标,其在天然水体中以溶解态、颗粒态等形态存在。研究水中含沙量的改变对不同形态磷浓度的影响,对磷污染控制有着重要意义。选取三峡水库干流为研究对象,采用Mann-Kendall非参数检验法和Pearso... 磷是水环境质量评价和污染控制考核的重要指标,其在天然水体中以溶解态、颗粒态等形态存在。研究水中含沙量的改变对不同形态磷浓度的影响,对磷污染控制有着重要意义。选取三峡水库干流为研究对象,采用Mann-Kendall非参数检验法和Pearson相关系数分析了该河段含沙量变化对总磷、溶解磷、颗粒磷等不同形态磷浓度的影响。结果表明:①2003~2019年三峡水库干流的平均流量无明显变化,含沙量则明显减少。②总磷浓度在2003~2012年间起伏波动、缓慢上升,2013~2019年则持续下降;溶解磷浓度呈先上升后下降的趋势,各断面峰值出现在2013、2014年;颗粒态磷浓度呈波动下降趋势。③与2003~2012年浓度均值相比,2013~2019年浑浊水样磷浓度、沉降水样磷浓度以及颗粒磷浓度分别下降了40%,25%和65%;溶解磷浓度则出现明显上升,库尾朱沱断面、变动回水区寸滩断面上升约60%,常年回水区清溪场和万县断面分别上升约20%和12%;溶解磷/沉降水样磷的比值快速上升,2013~2019年溶解磷/沉降水样磷均达到68%以上。④在新水沙条件影响下,三峡水库干流不同形态磷浓度已发生明显改变,最易被浮游生物利用的溶解磷已成为三峡水库干流磷的主要存在形式。研究成果可为三峡库区营养盐控制和治理提供科学依据。 展开更多
关键词 总磷 溶解磷 颗粒磷 含沙量 Mann-Kendall非参数检验 三峡水库
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基于组合模型的球员贡献度评价
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作者 代浩然 曹文芹 《山东理工大学学报(自然科学版)》 CAS 2024年第3期71-78,共8页
介绍了两种评价球员贡献度的统计模型,基于组合模型的优势,提出了1个组合评价模型,以2021—2022年NBA季后赛为例,利用非参数统计中Friedman检验进行了实证分析。通过基于熵权法改进的Topsis、主成分综合评价与组合模型3种评价模型来探究... 介绍了两种评价球员贡献度的统计模型,基于组合模型的优势,提出了1个组合评价模型,以2021—2022年NBA季后赛为例,利用非参数统计中Friedman检验进行了实证分析。通过基于熵权法改进的Topsis、主成分综合评价与组合模型3种评价模型来探究2021—2022年NBA总冠军金州勇士队球员的贡献,并对其贡献进行排名,采用Friedman检验得到3种模型的结论基本一致。 展开更多
关键词 非参数统计 相关分析 组合模型 Friedman检验
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基于短行程分析法的列车牵引系统典型运行工况构建
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作者 鲁秀龙 郭艺丹 +2 位作者 程浩 邓敏 邹晓阳 《控制与信息技术》 2024年第3期59-65,共7页
为解决列车牵引系统在长距离、多工况运行时额定点的效率测试结果不能准确反映其实际能效水平,以及目前缺乏典型运行工况支撑牵引系统能效水平评估并指导产品节能设计等问题,文章提出了一种站点式短行程分析结合非参数检验构建铁路列车... 为解决列车牵引系统在长距离、多工况运行时额定点的效率测试结果不能准确反映其实际能效水平,以及目前缺乏典型运行工况支撑牵引系统能效水平评估并指导产品节能设计等问题,文章提出了一种站点式短行程分析结合非参数检验构建铁路列车牵引系统典型运行工况的方法。其首先对短行程进行划分、筛选及随机组合,然后通过非参数检验选取最佳短行程组合。文章采用该方法以某型电力机车牵引系统为例构建了其典型运行工况,采用运行特征参数值误差分析和车速-牵引力(V-F)分布概率二维矩阵相似度对该方法进行验证。结果显示,所构建的典型运行工况与所采样数据特征值偏差为4.54%,V-F分布概率矩阵相似性为98.06%,这表明所提方法可较为准确地反映列车牵引系统实际运行特性,所构建的典型运行工况与列车牵引系统实际运行情况具有较高的吻合度,可用于列车牵引系统节能设计及能效水平评估。 展开更多
关键词 牵引系统 能效 典型运行工况 短行程分析法 非参数检验
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Use of Pearson’s Chi-Square for Testing Equality of Percentile Profiles across Multiple Populations
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作者 William D. Johnson Robbie A. Beyl +3 位作者 Jeffrey H. Burton Callie M. Johnson Jacob E. Romer Lei Zhang 《Open Journal of Statistics》 2015年第5期412-420,共9页
In large sample studies where distributions may be skewed and not readily transformed to symmetry, it may be of greater interest to compare different distributions in terms of percentiles rather than means. For exampl... In large sample studies where distributions may be skewed and not readily transformed to symmetry, it may be of greater interest to compare different distributions in terms of percentiles rather than means. For example, it may be more informative to compare two or more populations with respect to their within population distributions by testing the hypothesis that their corresponding respective 10th, 50th, and 90th percentiles are equal. As a generalization of the median test, the proposed test statistic is asymptotically distributed as Chi-square with degrees of freedom dependent upon the number of percentiles tested and constraints of the null hypothesis. Results from simulation studies are used to validate the nominal 0.05 significance level under the null hypothesis, and asymptotic power properties that are suitable for testing equality of percentile profiles against selected profile discrepancies for a variety of underlying distributions. A pragmatic example is provided to illustrate the comparison of the percentile profiles for four body mass index distributions. 展开更多
关键词 Asymptotic CHI-SQUARE test EQUALITY of PERCENTILES Large Sample test MEDIAN test nonparametric Methods
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A Simple Chi-Square Statistic for Testing Homogeneity of Zero-Inflated Distributions
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作者 William D. Johnson Jeffrey H. Burton +1 位作者 Robbie A. Beyl Jacob E. Romer 《Open Journal of Statistics》 2015年第6期483-493,共11页
Zero-inflated distributions are common in statistical problems where there is interest in testing homogeneity of two or more independent groups. Often, the underlying distribution that has an inflated number of zero-v... Zero-inflated distributions are common in statistical problems where there is interest in testing homogeneity of two or more independent groups. Often, the underlying distribution that has an inflated number of zero-valued observations is asymmetric, and its functional form may not be known or easily characterized. In this case, comparisons of the groups in terms of their respective percentiles may be appropriate as these estimates are nonparametric and more robust to outliers and other irregularities. The median test is often used to compare distributions with similar but asymmetric shapes but may be uninformative when there are excess zeros or dissimilar shapes. For zero-inflated distributions, it is useful to compare the distributions with respect to their proportion of zeros, coupled with the comparison of percentile profiles for the observed non-zero values. A simple chi-square test for simultaneous testing of these two components is proposed, applicable to both continuous and discrete data. Results of simulation studies are reported to summarize empirical power under several scenarios. We give recommendations for the minimum sample size which is necessary to achieve suitable test performance in specific examples. 展开更多
关键词 Asymptotic CHI-SQUARE test EQUALITY of QUANTILES Large Sample test nonparametric test Percentile Profiles ZERO-INFLATED DISTRIBUTIONS
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Comparison of Two Sample Tests Using Both Relative Efficiency and Power of Test
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作者 Edith Uzoma Umeh Nkiru Obioma Eriobu 《Open Journal of Statistics》 2016年第2期331-345,共15页
This paper, comparison of two sample tests, is motivated by the fact that in the test of significant difference between two independent samples, numerous methods can be adopted;each may lead to significant different r... This paper, comparison of two sample tests, is motivated by the fact that in the test of significant difference between two independent samples, numerous methods can be adopted;each may lead to significant different results;this implies that wrong choice of test statistic could lead to erroneous conclusion. To prevent misleading information, there is a need for proper investigation of some selected methods for test of significant difference between variables/subjects most especially, independent samples. The paper examines the efficiency and sensitivity of four test statistics to ascertain which test performs better. Based on the results, the relative efficiency favours median test as being more efficient than modified median test for both symmetric and asymmetric distributions. In terms of power of test, median test is more sensitive than Modified Median (MMED) test since it has higher power irrespective of the sample sizes for both symmetric and asymmetric distribution. In terms of relative efficiency for asymmetric distribution Modified Mann-Whitney U test is more efficient than Mann-Whitney U test (MMWU), and then for symmetric distribution, Mann-Whitney U test (MMWU) is more efficient than Modified Mann-Whitney in sample size of 5;but for other sample sizes considered Modified Mann-Whitney U test (MMWU) is better than Mann-Whitney. Using power of test for both symmetric and asymmetric distributions, Mann-Whitney is more sensitive than Modified Mann-Whitney U test (MMWU) because it has higher power. 展开更多
关键词 ASYMMETRIC SYMMETRIC nonparametric test Two Sample tests Power of test Relative Efficiency
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Hypothesis Testing of Population Percentiles via the Wald Test with Bootstrap Variance Estimates
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作者 William D. Johnson Jacob E. Romer 《Open Journal of Statistics》 2016年第1期14-24,共11页
Testing the equality of percentiles (quantiles) between populations is an effective method for robust, nonparametric comparison, especially when the distributions are asymmetric or irregularly shaped. Unlike global no... Testing the equality of percentiles (quantiles) between populations is an effective method for robust, nonparametric comparison, especially when the distributions are asymmetric or irregularly shaped. Unlike global nonparametric tests for homogeneity such as the Kolmogorv-Smirnov test, testing the equality of a set of percentiles (i.e., a percentile profile) yields an estimate of the location and extent of the differences between the populations along the entire domain. The Wald test using bootstrap estimates of variance of the order statistics provides a unified method for hypothesis testing of functions of the population percentiles. Simulation studies are conducted to show performance of the method under various scenarios and to give suggestions on its use. Several examples are given to illustrate some useful applications to real data. 展开更多
关键词 BOOTSTRAP Hypothesis testing nonparametric Methods Percentile Profiles Wald test
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