Probability Addition Rule

Front

What is the Probability Addition Rule?

Back

The Probability Addition Rule states that for any two events A and B, the probability of A or B occurring is given by: P(A or B) = P(A) + P(B) - P(A and B).

Front

Define mutually exclusive events.

Back

Mutually exclusive events are events that cannot occur at the same time. If one event occurs, the other cannot.

Front

What is the formula to calculate the probability of A or B when events are not mutually exclusive?

Back

P(A or B) = P(A) + P(B) - P(A and B).

Front

If P(A) = 0.4 and P(B) = 0.3, what is P(A or B) if A and B are mutually exclusive?

Back

P(A or B) = P(A) + P(B) = 0.4 + 0.3 = 0.7.

Front

What does it mean if two events are independent?

Back

Two events are independent if the occurrence of one event does not affect the probability of the other event occurring.

Front

How do you calculate the probability of independent events A and B?

Back

For independent events, P(A and B) = P(A) * P(B).

Front

What is the probability of spinning purple or green if the spinner has 6 equal sections with 2 purple and 4 green?

Back

P(purple or green) = P(purple) + P(green) = \frac{2}{6} + \frac{4}{6} = \frac{6}{6} = 1.

Front

If P(A) = 0.4 and P(B) = 0.25, and P(A and B) = 0.13, what is P(A or B)?

Back

P(A or B) = P(A) + P(B) - P(A and B) = 0.4 + 0.25 - 0.13 = 0.52.

Front

What is the probability of choosing a number less than 5 or a shaded number if P(shaded) = 4/8 and P(<5) = 4/8?

Back

P(shaded or <5) = P(shaded) + P(<5) - P(shaded and <5) = \frac{4}{8} + \frac{4}{8} - \frac{2}{8} = \frac{6}{8}.

Front

What is the probability of event A if P(A) = 0.4?

Back

The probability of event A occurring is 0.4, meaning there is a 40% chance of A happening.