求教SAS的MDC模块技术mixed logit 模块的计算方法
data origdata;input ttime1 ttime2 ttime3 choice @@;
datalines;
16.481 16.196 23.892 15.123 11.373 14.182 2
19.469 8.82220.819 2 18.847 15.649 21.282
12.578 10.671 18.335 2 11.513 20.582 27.838 1
10.651 15.537 17.418 1 8.35915.675 21.051
11.679 12.668 23.104 1 23.237 10.356 21.346 2
13.236 16.019 10.087 3 20.052 16.861 14.168 3
18.917 14.764 21.564 2 18.2 6.86819.095 2
10.777 16.554 15.938 1 20.003 6.3779.3142
19.768 8.52318.962 8.15113.845 17.643 2
22.173 18.045 15.535 1 13.134 11.067 19.108 2
11.666 10.758 16.445 1 17.211 15.201 17.059 3
14.051 14.247 15.764 1 14.685 10.811 12.361 3
13.9316.227 22.024 1 15.237 14.345 19.984 2
10.8411.071 10.188 1 16.841 11.224 13.417 2
13.913 16.991 26.618 3 13.089 9.82219.162 2
16.626 10.725 15.285 3 13.477 15.509 24.421 2
20.851 14.557 19.8 2 11.365 12.673 22.212 2
13.296 10.076 17.812 15.417 14.103 21.051
15.938 11.1819.851 2 19.034 14.125 19.764 2
10.466 12.841 18.541 15.799 16.979 13.074 3
12.713 15.105 13.629 2 16.908 10.958 19.713 2
17.098 6.85314.502 2 18.608 14.286 18.301 2
11.059 10.812 20.121 1 15.641 10.754 24.669 2
7.82218.949 16.904 1 12.824 5.69719.183 2
11.852 12.147 15.672 2 15.557 8.30722.286 2
;
data newdata(keep=pid decision mode ttime1 ttime2 ttime3);
set origdata;
array tvec{3} ttime1-ttime3;
retain pid 0;
pid + 1;
do i = 1 to 3;
mode = i;
ttime = tvec{i};
decision = ( choice = i);
output;
end;
run;
proc mdc data=newdata type=mixedlogit ;
model decision = ttime1 ttime2 ttime3 / nchoice=3
mixed=(normalparm = ttime1 ttime2 ttime3);
id pid;
run;
得到的结果是这样的：
SAS 系统
MDC 过程
混合多项式 Logit 估计
参数估计
参数 自由度 估计 标准
误差 t 值 近似
Pr > |t|
ttime1_M 0 1E-6 . . .
ttime1_S 0 1E-6 . . .
ttime2_M 0 1E-6 . . .
ttime2_S 0 1E-6 . . .
ttime3_M 0 1E-6 . . .
ttime3_S 0 1E-6 . . .
怎么计算mixedlogit模块的参数呢？？
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