Biostatistics series module 3: Comparing groups: Numerical variables

统计 数学 正态性 方差分析 正态性检验 拟合优度 参数统计 人口 样本量测定 正态分布 数据集 统计假设检验 医学 环境卫生
作者
Avijit Hazra,Nithya Gogtay
出处
期刊:Indian Journal of Dermatology [Medknow]
卷期号:61 (3): 251-251 被引量:209
标识
DOI:10.4103/0019-5154.182416
摘要

Numerical data that are normally distributed can be analyzed with parametric tests, that is, tests which are based on the parameters that define a normal distribution curve. If the distribution is uncertain, the data can be plotted as a normal probability plot and visually inspected, or tested for normality using one of a number of goodness of fit tests, such as the Kolmogorov-Smirnov test. The widely used Student's t-test has three variants. The one-sample t-test is used to assess if a sample mean (as an estimate of the population mean) differs significantly from a given population mean. The means of two independent samples may be compared for a statistically significant difference by the unpaired or independent samples t-test. If the data sets are related in some way, their means may be compared by the paired or dependent samples t-test. The t-test should not be used to compare the means of more than two groups. Although it is possible to compare groups in pairs, when there are more than two groups, this will increase the probability of a Type I error. The one-way analysis of variance (ANOVA) is employed to compare the means of three or more independent data sets that are normally distributed. Multiple measurements from the same set of subjects cannot be treated as separate, unrelated data sets. Comparison of means in such a situation requires repeated measures ANOVA. It is to be noted that while a multiple group comparison test such as ANOVA can point to a significant difference, it does not identify exactly between which two groups the difference lies. To do this, multiple group comparison needs to be followed up by an appropriate post hoc test. An example is the Tukey's honestly significant difference test following ANOVA. If the assumptions for parametric tests are not met, there are nonparametric alternatives for comparing data sets. These include Mann-Whitney U-test as the nonparametric counterpart of the unpaired Student's t-test, Wilcoxon signed-rank test as the counterpart of the paired Student's t-test, Kruskal-Wallis test as the nonparametric equivalent of ANOVA and the Friedman's test as the counterpart of repeated measures ANOVA.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
星辰大海应助拓小八采纳,获得10
刚刚
Tao发布了新的文献求助10
1秒前
1秒前
Tangviva1988发布了新的文献求助10
1秒前
阳光沛柔发布了新的文献求助10
2秒前
SYLH应助cyn0762采纳,获得30
3秒前
7秒前
打打应助Tine采纳,获得30
8秒前
研友_VZG7GZ应助EED采纳,获得10
9秒前
缥缈问柳应助wjw采纳,获得10
9秒前
DijiaXu应助朝朝采纳,获得10
11秒前
sanyecai完成签到,获得积分10
11秒前
李健的小迷弟应助高铭泽采纳,获得10
14秒前
Zsl121完成签到,获得积分10
15秒前
15秒前
爆米花应助肖肖采纳,获得10
16秒前
16秒前
冬至完成签到,获得积分10
17秒前
18秒前
shenzhou9完成签到,获得积分10
18秒前
量子星尘发布了新的文献求助10
18秒前
19秒前
lll完成签到,获得积分20
21秒前
欣喜豌豆完成签到,获得积分10
23秒前
彭于晏应助雨过天晴采纳,获得10
23秒前
李健的小迷弟应助唐_采纳,获得10
24秒前
云辞忧发布了新的文献求助10
24秒前
华仔应助Livrik采纳,获得10
24秒前
EED发布了新的文献求助10
25秒前
26秒前
27秒前
28秒前
赘婿应助hhhi采纳,获得10
28秒前
领导范儿应助康康采纳,获得10
29秒前
李健的小迷弟应助blue采纳,获得10
29秒前
31秒前
31秒前
可爱的函函应助智慧爷爷采纳,获得10
31秒前
研友_VZG7GZ应助dsdsd采纳,获得10
31秒前
高铭泽发布了新的文献求助10
33秒前
高分求助中
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
‘Unruly’ Children: Historical Fieldnotes and Learning Morality in a Taiwan Village (New Departures in Anthropology) 400
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
基于可调谐半导体激光吸收光谱技术泄漏气体检测系统的研究 350
Robot-supported joining of reinforcement textiles with one-sided sewing heads 320
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3988868
求助须知:如何正确求助?哪些是违规求助? 3531255
关于积分的说明 11253071
捐赠科研通 3269858
什么是DOI,文献DOI怎么找? 1804822
邀请新用户注册赠送积分活动 881994
科研通“疑难数据库(出版商)”最低求助积分说明 809035