setwd("C:/Users/11565/Desktop/合併二")
shuju <- read.csv("資料.csv",header = T)
library(psych)
head(shuju)
attach(shuju)
head(mtcars)
aggregate(shuju,by= list(state),FUN = mean,na.rm = T)
tapply(shuju[,3],shuju$year,mean)#每次只能求一列
aggregate(shuju[,3:4],list(shuju[,2]),mean)#每次可以求多列
mean_1 <- aggregate(shuju[,3:6],list(shuju[,2]),mean)
detach(shuju)
attach(mean_1)
head(mean_1)
mean_1$pcap <- mean_1$pcap/10
mean_1$Group.1<- as.numeric(mean_1$Group.1)
plot(Group.1,pcap,lty= 3,pch = 21,ylim = c(1000,3000))#畫不出兩幅圖的原因很可能是兩個變數數量級存在問題

lines(Group.1,hwy/10,lty = 2,pch = 22)#畫折現圖要先看一下x對應的y和y的數量級如何
str(mean_1)