Random Normal Mixture([20, 40], [10, 10], [.8, .2])
Or if you want to use variables for the vectors
M= matrix(evallist({mean1 = 20, Mean2 = 40, SD1 = 10, SD2 = 10, Probability1 = 0.8, Probability2 = 0.2}));
//Example
dt = New Table("Test",
add rows(500),
New Column("RNM", Formula(Random Normal Mixture(M[1 :: 2], M[3 :: 4], M[5 :: 6])))
);
dt << Distribution(Continuous Distribution(Column(:RNM)));