如图，x1-x5与m之间的路径系数都是相同的，不知道为什么会出现这样的情况。具体的inp如下：
DATA: FILE IS beta.dat;
VARIABLE: NAMES ARE x1-x5 m1-m3 y1;
usevariables are x1-x5 m1-m3 y1
Analysis: bootstrap=1000;
MODEL:
M by m1*m2-m3;
y1 on x1 x2 x3 x4 x5;
M on x1 x2 x3 x4 x5 (a);
y1 on x1 x2 x3 x4 x5
      M (b);
MODEL CONSTRAINT:
new (H);
H=a*b;
OUTPUT:
standardized cinterval (bcbootstrap);