problem3.m

一个比较简单的模式识别问题。用female.txt 和male.txt 的数据作为训练样本集

female = dlmread('female.txt');
male   = dlmread('male.txt');
set    = dlmread('set3.txt');
[favg, fsig] = normfit(female(:,1));
[mavg, msig] = normfit(male(:,1));
[length,width] = size(set);
ma = 0.75;
fe = 0.25;
error1 = 0;
error2 = 0;
x=10;
for i = 1:length
    Px = normpdf(set(i,1),favg,fsig)*fe + normpdf(set(i,1),mavg,msig)*ma;
    Pm = normpdf(set(i,1),mavg,msig)*ma/Px;
    Pf = normpdf(set(i,1),favg,fsig)*fe/Px;
    Pm = Pm*x;
    if Pm > Pf
        if set(i,3) ==2
            error1 = error1 + 1;
        end
    else
        if set(i,3) ==1
            error2 = error2 + 1;
        end
    end
end
errorratio = (error1+error2)/length