A company held a lottery to celebrate New Year's Day. Four balls marked with the numbers 1000, 800, 600 and 0 were placed in the lottery box prepared at the scene.

Let ξ represent the bonus after touching the ball, because the ball touched by the participants is marked with the numbers1000,800,600,0,

When you touch the ball marked with the number 0, you can touch it again.

But the bonus is halved, 500, 400, 300 and 0 respectively.

Then all possible values of ξ are1000,800,600,500,400,300,0.

According to the meaning, p (ξ =1000) = p (ξ = 800) = p (ξ = 600) =14,

P(ξ= 500)= P(ξ= 400)= P(ξ= 300)= P(ξ= 0)= 1 16，

Then the distribution list of ξ is

The expected value of ∴ is e ξ =14 (1000+800+600)+16 (500+400+300+0) = 675 yuan.