class22.R

##使用資料庫Ecdat中Caschool
library(Ecdat)

## Loading required package: Ecfun

## 
## Attaching package: 'Ecfun'

## The following object is masked from 'package:base':
## 
##     sign

## 
## Attaching package: 'Ecdat'

## The following object is masked from 'package:datasets':
## 
##     Orange

pacman::p_load(Ecdat)
data("Caschool", package="Ecdat")
dta <- Ecdat::Caschool
##看一下項目
head(dta)

##   distcod  county                        district grspan enrltot teachers
## 1   75119 Alameda              Sunol Glen Unified  KK-08     195    10.90
## 2   61499   Butte            Manzanita Elementary  KK-08     240    11.15
## 3   61549   Butte     Thermalito Union Elementary  KK-08    1550    82.90
## 4   61457   Butte Golden Feather Union Elementary  KK-08     243    14.00
## 5   61523   Butte        Palermo Union Elementary  KK-08    1335    71.50
## 6   62042  Fresno         Burrel Union Elementary  KK-08     137     6.40
##   calwpct mealpct computer testscr   compstu  expnstu      str    avginc
## 1  0.5102  2.0408       67  690.80 0.3435898 6384.911 17.88991 22.690001
## 2 15.4167 47.9167      101  661.20 0.4208333 5099.381 21.52466  9.824000
## 3 55.0323 76.3226      169  643.60 0.1090323 5501.955 18.69723  8.978000
## 4 36.4754 77.0492       85  647.70 0.3497942 7101.831 17.35714  8.978000
## 5 33.1086 78.4270      171  640.85 0.1280899 5235.988 18.67133  9.080333
## 6 12.3188 86.9565       25  605.55 0.1824818 5580.147 21.40625 10.415000
##       elpct readscr mathscr
## 1  0.000000   691.6   690.0
## 2  4.583333   660.5   661.9
## 3 30.000002   636.3   650.9
## 4  0.000000   651.9   643.5
## 5 13.857677   641.8   639.9
## 6 12.408759   605.7   605.4

##將會用到的lattice(畫圖)、dplyr、tidyr、magrittr(語法指令)一次叫出
library(lattice)
library(dplyr)

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

library(tidyr)
library(magrittr)

## 
## Attaching package: 'magrittr'

## The following object is masked from 'package:tidyr':
## 
##     extract

##指定算出ratio，切割資料三等分
dta<- dta%>%
  mutate(ratio = enrltot/teachers,
       Reading = cut(readscr, breaks = quantile(readscr, probs = c(0, .33, .67, 1)), 
                              label = c("L", "M", "H"), ordered = T))
##檢查資料切割狀況
head(dta)

##   distcod  county                        district grspan enrltot teachers
## 1   75119 Alameda              Sunol Glen Unified  KK-08     195    10.90
## 2   61499   Butte            Manzanita Elementary  KK-08     240    11.15
## 3   61549   Butte     Thermalito Union Elementary  KK-08    1550    82.90
## 4   61457   Butte Golden Feather Union Elementary  KK-08     243    14.00
## 5   61523   Butte        Palermo Union Elementary  KK-08    1335    71.50
## 6   62042  Fresno         Burrel Union Elementary  KK-08     137     6.40
##   calwpct mealpct computer testscr   compstu  expnstu      str    avginc
## 1  0.5102  2.0408       67  690.80 0.3435898 6384.911 17.88991 22.690001
## 2 15.4167 47.9167      101  661.20 0.4208333 5099.381 21.52466  9.824000
## 3 55.0323 76.3226      169  643.60 0.1090323 5501.955 18.69723  8.978000
## 4 36.4754 77.0492       85  647.70 0.3497942 7101.831 17.35714  8.978000
## 5 33.1086 78.4270      171  640.85 0.1280899 5235.988 18.67133  9.080333
## 6 12.3188 86.9565       25  605.55 0.1824818 5580.147 21.40625 10.415000
##       elpct readscr mathscr    ratio Reading
## 1  0.000000   691.6   690.0 17.88991       H
## 2  4.583333   660.5   661.9 21.52466       M
## 3 30.000002   636.3   650.9 18.69723       L
## 4  0.000000   651.9   643.5 17.35714       M
## 5 13.857677   641.8   639.9 18.67133       L
## 6 12.408759   605.7   605.4 21.40625       L

##開心用xyplot指令畫圖
xyplot(readscr~ratio|Reading,data=dta,
       type=c("p","g","r"),layout=c(3,1),
       xlab="Student-Teacher Ratio",
       ylab="Reading Score")