7th Grade · Statistics & Probability
Compound Event
7.SP.C.8
Definition
An event that combines two or more simple events. 'AND' events require all conditions to be met (intersection). 'OR' events require at least one condition (union).
Examples
- P(even AND heads) when rolling a die and flipping a coin: 3/12 = 1/4.
- P(roll a 1 OR a 6) = 2/6 = 1/3.
Key rule
AND usually gives a smaller probability; OR usually gives a larger one.
Memory hook
AND needs both; OR needs at least one.