第6章 判别分析
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练习题
1)考虑两个数据集x1 = [3 7 2 4 4 7],x2 = [6 9 5 7 4 8]
(1)计算Fisher线性判别函数
library(MASS) library(openxlsx) x1 = c(3,2,4,6,5,4) x2 = c(7,4,7,9,7,8) y = c(1,1,1,2,2,2) (data1 = data.frame(x1,x2,y)) plot(data1[,-3]) text(x1,x2,y,adj = -0.5) 12345678
x1_bar = data1[1:3,-3] x1_bar 12
x2_bar = data1[4:6,-3] x2_bar 12
(x1_mean = apply(x1_bar,2,mean)) (x2_mean = apply(x2_bar,2,mean)) 12
Sp = matrix(c(1,1,1,2),ncol = 2) Sp_re = solve(Sp) (2 * cov(x1_bar) + 2 * cov(x2_bar)) /12