The success numbers of the four experiments are 1.234 respectively.
P(X= 1)=C4 selection 1x (5/9) (4/9) 3.
P(x=2)=C4 Choose 2x (5/9) 2 (4/9) 2.
P(X=3)=C4 Choose 3x (5/9) 3 (4/9).
P(x=4)=C4 Select 4 (5/9) 4.
Mathematical expectation e =1XP1+2xp2+3xp3+4xp4.
Variance d = (xi-ex) 2xpi cumulative x from 1 to 4 p, and also from 1 to 4.