n种统计方法的应用条件

一parameter test
numerical data
1.Z:independence,normality,homogeneity
used in variance of population is known,or sample size is large(n＞50,n1+n2＞60)
2.t:independence,normality,homogeneity(INH)
used in variance of population is unknown,or sample sizw is small
one sample
two independent sample
paired sample
(df=n-1)
3.ANOV A(F test):INH
used in comparison of more than two means of groups.
pletely randomized design(df of error =N-g)
b.randomized block design(df of error=(g-1)(k-1))
tin square design
(b and c can control confounding factors)
further:want to know which pairwise groups have significant difference
a.SNKq unplaned comparison
b.Dunnett t:planed comparison
c.LSDt:compare choosen two groups
categorical data
chi square test:usd in
a.how closely an observed distribution matches expected distribution(goodness of fit)
b.whether two variables are independent
c.whether the difference of proportion is significant
1.fourfold table df=1
n≥40,E≥5:pearson chi square test
1≤E＜5:Yate's continuity correction
n＜40:fisher's exact test
2.paired fourfold table
b＋c＜40:continuity correction
used in:to same objects,different methods
3.R*C table :df=(r-1)(c-1)
cell numbers of E＜5 more than 1/5,use fisher's exact test
phi coefficient ,cramer's V,contigency coefficient are the measures of association for two categorical variables
二.non parameter test
1.wilcoxon signed rank test :used in paired sample and one sample ,when they do not satisfy the condition of parameter test.(statistics:T-,T+任选)
当n大于50无法查表时，T~N(n(n+1)/4,n(n+1)(2n+1)/24)
且当n不足够大时，需要continuity correction
当秩次重复超过1/5时，Zc
2.wilcoxon test for two independent sample:混合编秩，分别求和(T1,T2,选n较小者的T)
3.rank sum test for ordinal data.对于单向有序，选用行列表检验时无法得出疗效差别时
4.K-W test for :the number of groups more than two(statistics:H)
三.regression
1.simple linear regression :used in analysis of the influence of explanatory variable(independent variable) to the outcome variable(dependent variable)
a.X,Y are numerical data
b.X,Y have linear relationship
c.Y are nomal distribution for each given X
d.observations are independence
e.equal variance
(line)
几个概念:
linear regression model
coefficience of determinationR^2
residual
residual standard deviation
residual plot(residual analysis)
2.multiple linear regression:对Y的条件和simple linear regression一样，X可以是numerical data,binary data,ordinal data
几个概念:
opimum subset regression
stepwise regression
adjust R^2
dummy variable
3.logistic regression:Y is binary data,X is numerical,binary,ordinal ed to find the etiology of diseases,because the coefficient of logistic regression β has relationship with OR 概念:
maximum likelihood function
四correlation
1.linear correlation:pearson correlation analysis
要求XY服从双变量正态分布(binariate normal distribution X,Y,e~N),才能用tr进行假设检验估计总体相关系数(且tr=tb，df=n-2)
2.rank correlation:spearman correlation
XY不服从双变量正太分布时
3.association of two categorical variables
phi coefficient
cramer v
continuity coefficient。