Topic/SkillTopic:Definition/Tips
Basic Probability Example
1. Probability The likelihood/chance of something
happening.
Is expressed as a number between 0
(impossible) and 1 (certain).
Can be expressed as a fraction, decimal,
percentage or in words (likely, unlikely,
even chance etc.)
2. Probability P(A) refers to the probability that event A P(Red Queen) refers to the probability
Notation will occur. of picking a Red Queen from a pack of
cards.
3. Theoretical Number of Favourable Outcomes Probability of rolling a 4 on a fair 6-
Probability Total Number of Possible Outcomes 1
sided die = .
6
4. Relative Number of Successful Trials A coin is flipped 50 times and lands on
Frequency Total Number of Trials Tails 29 times.
The relative frequency of getting Tails
29
= .
50
5. Expected To find the number of expected outcomes, The probability that a football team
Outcomes multiply the probability by the number of wins is 0.2 How many games would
trials. you expect them to win out of 40?
0.2 × 40=8 games
6. Exhaustive Outcomes are exhaustive if they cover the When rolling a six-sided die, the
entire range of possible outcomes. outcomes 1, 2, 3, 4, 5 and 6 are
exhaustive, because they cover all the
The probabilities of an exhaustive set of possible outcomes.
outcomes adds up to 1.
7. Mutually Events are mutually exclusive if they Examples of mutually exclusive events:
Exclusive cannot happen at the same time.
- Turning left and right
The probabilities of an exhaustive set of - Heads and Tails on a coin
mutually exclusive events adds up to 1.
Examples of non mutually exclusive
events:
- King and Hearts from a deck of cards,
because you can pick the King of
Hearts
Mr A. Coleman Glyn School
Basic Probability Example
1. Probability The likelihood/chance of something
happening.
Is expressed as a number between 0
(impossible) and 1 (certain).
Can be expressed as a fraction, decimal,
percentage or in words (likely, unlikely,
even chance etc.)
2. Probability P(A) refers to the probability that event A P(Red Queen) refers to the probability
Notation will occur. of picking a Red Queen from a pack of
cards.
3. Theoretical Number of Favourable Outcomes Probability of rolling a 4 on a fair 6-
Probability Total Number of Possible Outcomes 1
sided die = .
6
4. Relative Number of Successful Trials A coin is flipped 50 times and lands on
Frequency Total Number of Trials Tails 29 times.
The relative frequency of getting Tails
29
= .
50
5. Expected To find the number of expected outcomes, The probability that a football team
Outcomes multiply the probability by the number of wins is 0.2 How many games would
trials. you expect them to win out of 40?
0.2 × 40=8 games
6. Exhaustive Outcomes are exhaustive if they cover the When rolling a six-sided die, the
entire range of possible outcomes. outcomes 1, 2, 3, 4, 5 and 6 are
exhaustive, because they cover all the
The probabilities of an exhaustive set of possible outcomes.
outcomes adds up to 1.
7. Mutually Events are mutually exclusive if they Examples of mutually exclusive events:
Exclusive cannot happen at the same time.
- Turning left and right
The probabilities of an exhaustive set of - Heads and Tails on a coin
mutually exclusive events adds up to 1.
Examples of non mutually exclusive
events:
- King and Hearts from a deck of cards,
because you can pick the King of
Hearts
Mr A. Coleman Glyn School
