Discrete Probability
CMSC 203 Discrete Structures 1
, Discrete Probability
Everything you have learned about counting
constitutes the basis for computing the
probability of events to happen.
In the following, we will use the notion experiment
for a procedure that yields one of a given set of
possible outcomes.
This set of possible outcomes is called the sample
space of the experiment.
An event is a subset of the sample space.
CMSC 203 Discrete Structures 2
, Discrete Probability
If all outcomes in the sample space are equally
likely, the following definition of probability
applies:
The probability of an event E, which is a subset of
a finite sample space S of equally likely outcomes,
is given by p(E) = |E|/|S|.
Probability values range from 0 (for an event that
will never happen) to 1 (for an event that will
always happen whenever the experiment is carried
out).
CMSC 203 Discrete Structures 3