==============================================================================
       y=1       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const         -0.2794      0.612     -0.457      0.648      -1.479       0.920
x1            -0.0119      0.034     -0.350      0.727      -0.079       0.055
x2             0.2946      0.093      3.152      0.002       0.111       0.478
x3            -0.0257      0.007     -3.873      0.000      -0.039      -0.013
x4             0.0897      0.069      1.297      0.195      -0.046       0.225
------------------------------------------------------------------------------
       y=2       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const         -1.7392      0.720     -2.414      0.016      -3.151      -0.327
x1            -0.0941      0.039     -2.415      0.016      -0.170      -0.018
x2             0.3838      0.108      3.559      0.000       0.172       0.595
x3            -0.0230      0.008     -2.914      0.004      -0.038      -0.008
x4             0.2451      0.080      3.053      0.002       0.088       0.402
------------------------------------------------------------------------------
       y=3       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const         -3.0091      1.069     -2.815      0.005      -5.104      -0.914
x1            -0.1115      0.057     -1.965      0.049      -0.223      -0.000
x2             0.5641      0.159      3.557      0.000       0.253       0.875
x3            -0.0156      0.011     -1.391      0.164      -0.038       0.006
x4             0.0687      0.119      0.577      0.564      -0.165       0.302
------------------------------------------------------------------------------
       y=4       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const         -6.5607      0.870     -7.540      0.000      -8.266      -4.855
x1            -0.0949      0.043     -2.183      0.029      -0.180      -0.010
x2             1.2668      0.128      9.897      0.000       1.016       1.518
x3            -0.0109      0.008     -1.315      0.189      -0.027       0.005
x4             0.3067      0.088      3.475      0.001       0.134       0.480
------------------------------------------------------------------------------
       y=5       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const         -6.0760      0.774     -7.851      0.000      -7.593      -4.559
x1            -0.0967      0.039     -2.479      0.013      -0.173      -0.020
x2             1.3377      0.116     11.493      0.000       1.110       1.566
x3            -0.0198      0.008     -2.631      0.009      -0.035      -0.005
x4             0.3193      0.080      4.001      0.000       0.163       0.476
------------------------------------------------------------------------------
       y=6       coef    std err          z      P>|z|      [0.025      0.975]
------------------------------------------------------------------------------
const        -10.5973      0.957    -11.076      0.000     -12.473      -8.722
x1            -0.1447      0.042     -3.475      0.001      -0.226      -0.063
x2             2.0395      0.141     14.479      0.000       1.763       2.316
x3            -0.0129      0.008     -1.612      0.107      -0.029       0.003
x4             0.4576      0.085      5.352      0.000       0.290       0.625
==============================================================================