Probability - Addition Rule

Front

What is the Addition Rule in probability?

Back

The Addition Rule states that the probability of the occurrence of at least one of two events A or B is given by P(A or B) = P(A) + P(B) - P(A and B).

Front

If P(A) = 0.5 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) = 0.5 + 0.3 = 0.8.

Front

What does it mean for two events to be mutually exclusive?

Back

Two events are mutually exclusive if they cannot occur at the same time, meaning P(A and B) = 0.

Front

How do you calculate the probability of rolling a number greater than 3 on a 6-sided die?

Back

The numbers greater than 3 are 4, 5, and 6. So, P(greater than 3) = 3/6 = 1/2.

Front

What is the probability of selecting a yellow or green marble from a jar containing 1 red, 3 green, 2 blue, and 4 yellow marbles?

Back

Total marbles = 10. Yellow + Green = 4. So, P(yellow or green) = 4/10 = 2/5.

Front

In a probability problem, what does 'at least one' mean?

Back

'At least one' means one or more occurrences of an event, which can be calculated using the Addition Rule.

Front

What is the probability of an event that is certain to happen?

Back

The probability of a certain event is 1.

Front

What is the probability of an event that is impossible to happen?

Back

The probability of an impossible event is 0.

Front

If a spinner has 4 equal sectors, what is the probability of landing on one specific color?

Back

The probability of landing on one specific color is 1/4.

Front

How do you find the probability of two independent events A and B occurring together?

Back

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