* data from England and Denmark (from my 1985 Q&Q paper)
* to illustrate use of group variable
man 3
dim 2 5 5
lab C O D
mod {CO CD spe(OD,1a,C,b)}* spe command asks for OD association varying l-m over C
*mod {CO CD fac(OD,10,C,b)  } * C is group variable and b asks for unidiffed parameters
nec nco
*des [
*0 1 2 3 4
*1 0 5 6 7
*2 5 0 8 9
*3 6 8 0 10
*4 7 9 10 0
*]
dum 1 1 1
dat [
50 45 8 18 8	* E&W
28 174 84 154 55
11 78 110 223 96
14 150 185 714 447
0 42 72 320 411
18 17 16 4 2	* Denmark
24 105 109 59 21
23 84 289 217 95
8 49 175 348 198
6 8 69 201 246]