/* Example using uniform random number generator to obtain */
/* D values uniformly distributed in 2-cm d classes. */
Data one;
input dclass freq;
cards;
6 4
8 12
10 20
12 18
;
data two; set one;
retain seed 555; /* <== initialize seed to any value */
do i=1 to freq;
value = dbhclass - 1;
dbh = round(value + 2*uniform(seed), 0.01);
output;
end;
我不知道上面标红的是啥意思?请帮我解答下,谢谢!