setwd("D:/编程/统计建模与Ｒ软件/RSource/XueY/Chapter02")
例2.2:表2.1 计算体重与胸围的均值与标准差
weight<-c(35,40,40,42,37,45,43,37,44,42,41,39)
mean(weight) #计算体重均值
sd(weight) #计算体重标准差
chest<-c(60,74,64,71,72,68,78,66,70,65,73,75)
mean(chest)
sd(chest)
制图
1.散点图
plot(weight,chest)
2.体重直方图
hist(weight)
例2.3: 设有文本文件exam0203.txt 文件的读取
数据如下：
Name Sex Age Height Weight
Alice F 13 56.5 84.0
Becka F 13 65.3 98.0
Gail F 14 64.3 90.0
Karen F 12 56.3 77.0
Kathy F 12 59.8 84.5
Mary F 15 66.5 112.0
Sandy F 11 51.3 50.5
Sharon F 15 62.5 112.5
Tammy F 14 62.8 102.5
Alfred M 14 69.0 112.5
Duke M 14 63.5 102.5
Guido M 15 67.0 133.0
James M 12 57.3 83.0
Jeffrey M 13 62.5 84.0
John M 12 59.0 99.5
Philip M 16 72.0 150.0
Robert M 12 64.8 128.0
Thomas M 11 57.5 85.0
William M 15 66.5 112.0
rt<-read.table("exam0203.txt",head=TRUE);rt
lm.sol<-lm(Weight~Height,data=rt)
summary(lm.sol)
