>> o=corrcoef(r) o =
1.0000 0.3438 0.5834 0.7571 0.3438 1.0000 -0.4352 -0.3108 0.5834 -0.4352 1.0000 0.9407
0.7571 -0.3108 0.9407 1.0000
再用maltab求出相关矩阵的特征根 i,特征向量ti, 并求出对应的贡献率 i = i/ i和累计贡献率,表格如下:
可见,只需取前两个作为主成分即可表示满意指标。两个主成分y1,y2而y1占64.48%,y2占33.03%。
前两个标准化样本主成分表达式分别为:
z1 0.4775x1 0.1822x2 0.6196x3 0.5957x4z2 0.5423x1 0.8229x2 0.0134x3 0.1692x4
t =
-2.3970 0.2988 -0.1737 0.3543 0.2710 0.6878 0.4377 0.5211 -0.9922 1.7339 0.0064 1.2747 -0.2925 -0.1321 -0.7517 -0.8464 -1.0231 -1.0231 -1.0231 -0.3328 0.0616 1.2449 1.0477 1.0477 -1.5942 -0.8856 -0.6495 -0.1771 0.2952 0.7676 1.0037 1.2399
y1=[-1.9219 -0.5533 -0.8263 1.2998 -0.1081 0.04336 0.8961 0.9463]; >> y2=[-2.561 0.8758 -0.2794 -0.3711 0.4023 1.5696 0.1845 0.2721]; >> w=y1+y2
w =

