Special topics on traditional probability in senior high school

The second step of number extraction, 12 personal number extraction is "simultaneous".

If you have any questions about this topic, let's assume that in the number of 12 in the first step, the winning probability from 1 to 1 is 0, and the winning probability from 12 is1. In this way, in the second step, everyone's winning probability is the same 12, which means their winning probability is the same.

If you have to prove it, there is a stupid way.

Suppose the winning probability of the number 1 to 12 is f 1 to F 12, and F 1+F2+ ... is F 12 = 1 respectively.

Then the winning probability of everyone in the lottery is:

1/ 12 * f 1+ 1/ 12 * F2+……+ 1/ 12 * f 12

= 1/ 12(f 1+F2+……f 12)= 1/ 12

The second question, it doesn't matter, because steps 1 and 2 are independent of each other and do not affect the probability of events.

The third question, it doesn't matter, because talking can't let the lottery fly to you.