Probability of Compound Events Flashcards

Grade 7 · Math · Flashcards

Key terms and rules for calculating compound event probabilities.

Flashcards

Probability formula: P(event) = favorable outcomes ÷ total outcomes in the sample space
Compound event: An event that involves two or more simple events occurring together
Independent events: Events where the outcome of one does NOT affect the probability of the other
Dependent events: Events where the outcome of one DOES affect the probability of the other
Multiplication Rule (independent): P(A and B) = P(A) × P(B)
Multiplication Rule (dependent): P(A and B) = P(A) × P(B after A occurred)
Sample space: The set of ALL possible outcomes of an experiment
Counting outcomes in compound sample space: Multiply the number of outcomes for each individual event
Tree diagram: A diagram with branches showing each possible outcome at each stage of a compound experiment
With replacement: The item is returned before the next draw; events remain INDEPENDENT
Without replacement: The item is NOT returned; events become DEPENDENT and sample space shrinks
Sum of all probabilities: All probabilities in a sample space must sum to exactly 1
Organized list method: Systematically write out all outcomes of compound events in a table or list to count favorable ones