13.2

Mutually exclusive events

Lesson Objective:

IDENTIFY MUTUALLY EXCLUSIVE EVENTS

CALCULATE PROBABILITIES

Outcomes are mutually exclusive if they cannot happen at the same time

Example: rolling dice once and getting 6 and 2

Multiple Choice

1. When rolling a single die, the events of rolling an even number and rolling a ‘5’ are ...

• Mutually Exclusive

• Not Mutually Exclusive

Multiple Choice

2. When rolling a single die, the events of rolling an odd number and rolling a prime are ...

• Mutually Exclusive

• Not Mutually Exclusive

Multiple Choice

3. When rolling a single die, the events of rolling an even and an odd number are ...

• Mutually Exclusive

• Not Mutually Exclusive

Multiple Choice

4. If a spinner is numbered 1 – 8, when you spin it the events of spinning an even number and a number less than 4 are ...

• Mutually Exclusive

• Not Mutually Exclusive

Multiple Choice

5. Rolling an odd number and rolling an even number on a normal six-sided die are

• Mutually exclusive

• Not mutually exclusive

Multiple Choice

6. Rolling a prime number and rolling an even number on a normal six-sided die are

• Mutually exclusive

• Not mutually exclusive

If a set of mutually exclusive events covers all possible outcomes then their sum of probabilities is 1

Example: Lucius throws a biased coin.

The probability of getting tails is 0.7.

Therefore, the probability of getting heads is 1-0.7=0.3

Multiple Choice

Cyrus throws a biased coin. The probability of getting tails is 0.4.

Work out the probability of getting heads.

• 0.4

• 0.6

• 0.8

• 0.2

Multiple Choice

Bernard plants a sunflower seed. The probability that the seed will grow is 0.8.

Work out the probability of the seed not growing.

• 0.8

• 0.2

• 0.6

• 0.4

Multiple Choice

The chance of rolling a 2 is 1/6. What is the chance of not rolling a 2?

• 2/6

• 1/6

• 5/6

• not possible