A workshop produces 6 pieces of a product every day for three days, including 2 pieces on the first day, 1 piece on the second day and 1 piece on the third day. The quality inspection department

(1) Let the probability be p, which can be obtained according to the meaning of the question.

P=C34C36=420= 15。

(2) according to the meaning, ξ? Take 0, 1, 2, 3, and the probability that the product passes the inspection on the ith day is pi (I = 1, 2, 3).

Then P 1= 15, P2=P3=C35C36= 12.

∴p(ξ=0)=45× 12× 12= 15,p(ξ= 1)= 15× 12× 12+c 12×45× 12× 12=920，

P(ξ= 2)= 45× 12× 12+c 12× 15× 12 = 3 10，P(ξ= 3)= 15× 12× 12 = 120

The distribution list of ξ is:

eξ= 0× 15+ 1×920+2×3 10+3×