Year 8 Mathematics
Probability
Study Notes
SAMPLE SPACE
The sample space of an experiment is the set of all possible
outcomes of that experiment.
THE BASIC PROBABILITY LAW
P(E)=n(E)
n(S)
where P(E) = probability of an event
n(E) = number of favourable outcomes
n(S) = total number of possible outcomes in the sample space
RANGE OF PROBABILITIES
If an event is CERTAIN to occur, then its probability is 1.
If an event is IMPOSSIBLE, then its probability is 0.
0 ≤ P(E) ≤ 1
COMPLEMENTARY EVENTS
The probability of all outcomes in the sample space must add up to 1.
Therefore the probability of ‘an event not occurring is equal to
‘1 – probability of the event occurring’
P(E
__
)=1−P(E)
where
P(E
__
)
is the probability of the event not occurring
