### 基本统计分析 ################
install.packages("vcd")
install.packages("grid")
library(grid)
library(vcd)
head(Arthritis,50)
##生成频数表
mytable <- with(Arthritis,table(Improved))
#一维列联表
mytable
prop.table(mytable)
prop.table(mytable)*100
#二维列联表
mytable <- xtabs(~ Treatment + Improved,data = Arthritis)
prop.table(mytable)
#多维列联表
mytable <- xtabs(~ Treatment + Improved + Sex,data = Arthritis)
prop.table(mytable)
##独立性检验
#卡方独立性检验
mytable <- xtabs(~ Treatment + Improved,data = Arthritis)
chisq.te