onion23的博客

题目解析# 2.1x = matrix(c(1,2,3),byrow=F)y = matrix(c(4,5,6),byrow=F)# (1)# A * B 对应元素相乘# A %*% B 内积# A %o% B 外积e = matrix(rep(1,3),byrow=F)z = 2*x + y + ez# (2)x %*% y# (3)x %o% y# 2.2A = matrix(1:20,nrow=4,ncol=5,byrow=F)B =

上机练习及解析1）数据的读取数据：weight height4.17 1.755.58 1.85.18 1.656.11 1.94.5 1.744.61 1.915.17 1.754.53 1.85.33 1.655.14 1.94.81 1.744.17 1.914.41 1.753.59 1.85.87 1.653.83 1.96.03 1.744.89 1.914.32 1.754.69 1.8代码：# T1.1d = read.t

上机练习及解析10位同学的姓名、性别、年龄、身高、体重数据如下：Name Sex Age Height WeightAlice F 13 56.5 84.0Sandy F 11 51.3 50.5Sharon F 15 62.5 112.5Tammy F 14 62.8 102.5Alfred M 14 69.0 112.5Duke M 14 63.5 102.5Guido M 15 67.0 133

上机题目及解析1）先复制附录数据至文本文档，然后读取数据至文件data# T1setwd("C:/Users/87029/Desktop") # 设置当前工作路径data = read.table("data.txt",header=TRUE)data2）比值的计算weight和height的平方的比值存入bmi变量# T2data$bmi = data$weight/data$heightdata3）创建对象x, 其值为1:10, 使用write函数将其写入文件x.t

上机练习及解析1）计算y = sin(10*pi)*exp(-0.3+4^2)+log(23)/log(4)结果：[1] 2.2617812）x = sin(223/3)， y = x^2，z = y*10 ；求x+2y-5zx = sin(223/3)y = x^2z = y*10x + 2*y - 5*z结果：[1] -37.602553）建立起始值=3,增量值=5.5,终止值=44的一维数组xx = seq(3,44,by=5.5)结果.

** 使用课本：统计建模与R软件（黄色封面）上机题目及解析1）创建x的列表：7.3,6.8,0.005,9,12,2.4,18.9,0.9x = c(7.3,6.8,0.005,9,12,2.4,18.9,0.9)2）计算均值mean(x)3）减去均值x - mean(x)4）四舍五入，保留两位小数round(x,digits=2)5）计算2的前50次方，记为aa = 2^(1:50)6）计算1到50的平方，记为bb = (1:50)^2.