MONTECARLO:

names are y1-y6;
nobservations = 1500;
nreps = 1000;
seed = 56798;

!The patmiss and patprobs commands remain unchanged when a quadratic term is added;
patmiss = 
y1(0) y2(0) y3(0) y4(0) y5(1) y6(1)|
y1(0) y2(0) y3(0) y4(1) y5(0) y6(1)|
y1(0) y2(0) y3(1) y4(0) y5(0) y6(1)|
y1(0) y2(1) y3(0) y4(0) y5(0) y6(1)|
y1(1) y2(0) y3(0) y4(0) y5(0) y6(1)|
y1(0) y2(0) y3(0) y4(1) y5(1) y6(0)|
y1(0) y2(0) y3(1) y4(0) y5(1) y6(0)|
y1(0) y2(1) y3(0) y4(0) y5(1) y6(0)|
y1(1) y2(0) y3(0) y4(0) y5(1) y6(0)|
y1(0) y2(0) y3(1) y4(1) y5(0) y6(0)|
y1(0) y2(1) y3(0) y4(1) y5(0) y6(0)|
y1(1) y2(0) y3(0) y4(1) y5(0) y6(0)|
y1(0) y2(1) y3(1) y4(0) y5(0) y6(0)|
y1(1) y2(0) y3(1) y4(0) y5(0) y6(0)|
y1(1) y2(1) y3(0) y4(0) y5(0) y6(0);

patprobs = .066666|.066666|.066666|.066666|.066666|.066666|.066666|.066666|.066666|
.066666|.066666|.066666|.066666|.066666|.066666;

MODEL POPULATION:

icept linear quad | y1@0 y2@1 y3@2 y4@3 y5@4 y6@5;
[icept*20.58 linear*-1.748 quad*.18];
icept*191.55 linear*3.30;
icept with linear*-7.92;
y1-y6*135;
quad*0; icept with quad*0; linear with quad*0;

ANALYSIS:

type = missing;
COVERAGE = .0000001;

MODEL: 

icept linear quad| y1@0 y2@1 y3@2 y4@3 y5@4 y6@5;
y1-y6;