共分散（相関）の説明に使えそうな図

共分散や相関係数を説明するのに使えそうな図のセットです。

準備

# 準備
library(tidyverse)

## ─ Attaching packages ──────────────────── tidyverse 1.3.1 ─

## ✓ ggplot2 3.3.3     ✓ purrr   0.3.4
## ✓ tibble  3.1.2     ✓ dplyr   1.0.6
## ✓ tidyr   1.1.3     ✓ stringr 1.4.0
## ✓ readr   1.4.0     ✓ forcats 0.5.1

## ─ Conflicts ───────────────────── tidyverse_conflicts() ─
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()

old = theme_set(theme_gray(base_family = "HiraKakuProN-W3"))
set.seed(20180524)

# データ
x <- c(10,20,30,40,50)
y <- c(20,10,40,30,50)
df <- transform(cbind(x,y))
g1 <- ggplot(df,aes(x=x,y=y))+geom_point()
g1

平均偏差のプロット

g2 <- g1 +  geom_vline(xintercept = 30,lty=2)+
  geom_segment(x=x[1],xend=30,y=y[1],yend=y[1],lty=2,color='blue')+
  geom_segment(x=x[2],xend=30,y=y[2],yend=y[2],lty=2,color='blue')+
  geom_segment(x=x[3],xend=30,y=y[3],yend=y[3],lty=2,color='blue')+
  geom_segment(x=x[4],xend=30,y=y[4],yend=y[4],lty=2,color='blue')+
  geom_segment(x=x[5],xend=30,y=y[5],yend=y[5],lty=2,color='blue')
g2

g3 <- g1 + geom_hline(yintercept = 30,lty=2)+
  geom_segment(x=x[1],xend=x[1],y=y[1],yend=30,lty=2,color='brown')+
  geom_segment(x=x[2],xend=x[2],y=y[2],yend=30,lty=2,color='brown')+
  geom_segment(x=x[3],xend=x[3],y=y[3],yend=30,lty=2,color='brown')+
  geom_segment(x=x[4],xend=x[4],y=y[4],yend=30,lty=2,color='brown')+
  geom_segment(x=x[5],xend=x[5],y=y[5],yend=30,lty=2,color='brown')
g3

両方の偏差を重ねて描く

g4 <- g1 + geom_vline(xintercept = 30,lty=2)+
  geom_segment(x=x[1],xend=30,y=y[1],yend=y[1],lty=2,color='blue')+
  geom_segment(x=x[5],xend=30,y=y[5],yend=y[5],lty=2,color='blue') + 
  geom_hline(yintercept = 30,lty=2)+
  geom_segment(x=x[1],xend=x[1],y=y[1],yend=30,lty=2,color='brown')+
  geom_segment(x=x[5],xend=x[5],y=y[5],yend=30,lty=2,color='brown')

g4