Question

What is Probability of Compound Events?

Answer 1

It matters whether the events are independent or not.

Example
If you roll a die twice, the second roll is independent of the first, because a die doesn't have memory.

Probabilty of rolling two sixes
First: `P(1st=6)=1//6`
Second: `P(2nd=6)=1//6`

Probability of two sixes means:
First is 6 AND second is 6:
`P(1st=6)*P(2nd=6)=1//6 *1//6 = 1//36`

Probability of rolling more than 4 (i.e. 5 OR 6) in one try:
`P(5)=1//6`
`P(6)=1//6`
`P(>4)=P(5)+P(6)=1//6 +1//6=1//3`

General rule
If it's an AND situation multiply the chances
If it's an EITHER.. OR situation, you add