code 41765;
real procedure LOGISTICDENS(X, MU, SIGMA);
    value X, MU, SIGMA; real X, MU, SIGMA;
begin
    if SIGMA ≤ 0
    then STATAL3 ERROR(“LOGISTICDENS”, 3, SIGMA);
    X:= EXP(-(X - MU) / SIGMA);
    LOGISTICDENS:= X / ((1 + X) × (1 + X) × SIGMA)
end LOGISTICDENS;
eop