【数据分析入门】R语言入门之方差分析及应用实例

方差分析

library(multcomp)
attach(cholesterol)
table(trt)
##比较均值
aggregate(response,by=list(trt),FUN=mean) 
##方差分析
fit <- aov(response~trt,data =cholesterol )
fit
summary(fit)
fit.lm <- lm(response=trt,data=cholesterol)
fit.lm
summary(fit.lm)

aggregate比较均值，发现药物E的效果最好

f值越大，说明组间差异越显著
P值越小，越显著

fit.lm <- lm(response~trt,data =cholesterol ) 
fit.lm
summary(fit.lm)

litter
table(litter$dose)

attach(litter)
##比较均值
aggregate(weight,by=list(dose),FUN=mean) 

fit <- aov(weight~gesttime+dose,data =litter)

attach(ToothGrowth)
xtabs(~ supp+dose)
aggregate(len,by=list(supp,dose),FUN=mean)
> dose<-factor(dose)
> ToothGrowth$dose<-factor(ToothGrowth$dose)
> fit<-aov(len~supp+dose,data=ToothGrowth)
> summary(fit)

install.packages("HH") 
library(HH)
 interaction.plot(dose, supp,len, type="b",
                 col=c("red","blue"),pch=c(16,18),
                 main = "Interaction between Dose and supplenent type")

library(MASS)
attach(UScereal)
shelf <- factor(shelf)
aggregate(cbind(calories,fat,sugars),by=list(shelf),FUN=mean)
fit<-manova(cbind(calories,fat,sugars)~shelf)