Mutually Exclusive Events and Addition Rule

If a spinner is numbered 1 – 8, are the events of spinning an odd number and spinning an "8" mutually exclusive?

• Yes, these are Mutually Exclusive (no overlap).

• No, these are NOT Mutually Exclusive (overlap).

Is rolling an odd number and rolling an even number on a normal six-sided die mutually exclusive?

• Yes, these are Mutually Exclusive (no overlap).

• No, these are NOT Mutually Exclusive (overlap).

Which of the following shows how to determine P(football or basketball)?

Hint: Addition Rule

Two events are (a)   if they cannot happen at the same time

To find the probability of Event A OR Event B happening, what rule do we use?

• Addition Rule

• Multiplication Rule

• Complement Rule

• Subtraction Rule

Event A has a 1/2 chance of occurring, Event B has a 1/2 Chance of occurring and they have a 1/4 chance of happening at the same time. What is the probability of Event A or Event B happening?

• 1

• 1/2

• 1/4

• 3/4

Answer explanation

You use the Addition rule of Non-ME Events

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

If event A has a 1/4 chance of happening, event B has a 2/4 chance of happening, and there is a 1/3 chance that they Both happen. What is the probability of Event A or Event B happening?

• 5/12

• 2/4

• 3/4

• 12/5

If you are picking a card randomly from a deck of cards, the events of picking an ace and picking a 3 are mutually exclusive.

• True

• False

When rolling a single die, the events of rolling an even number and rolling a 5 are mutually exclusive.

• True

• False

If P(A) = 0.25, P(B) = 0.50, and P(A or B) = 0.65, are the events A and B mutually exclusive?

• Yes since P(A or B) = 0

• Yes since P(A) + P(B) = 0.75

• No since P(A and B) is not gven