This preview shows pages 1–2. Sign up to view the full content.
STA3032, Chapter 4, Page 1 of 4
Chapter 4 Probability
4.1 Definitions of Some Basic Terms
Definition
: A Statistical Experiment
is an experiment that has
Two or more outcomes
and
Uncertainty
as to which outcome will be observed.
Definition:
Probability is the study of uncertainty in a statistical experiment.
Definition:
S = Sample space
is the set of all possible outcomes of a statistical
experiment.
Definition:
An event
is any subset of the sample space.
Notes:
Since
S
and S
S, both
= { } and S are events.
= { } is called the impossible event and has probability zero, i.e., P(
) = 0.
S is called the definite event and has probability of 1, i.e., P(S) = 1.
Probability of any other event, say A, is between zero and one, i.e., 0 ≤ P(A) ≤
1 for any event A.
Set notation and set algebra, such as
,,
, and complement (
'
c
A
A
A
) are used in
defining some events. Venn diagrams will be helpful to understand some of the concepts
and solve some of the problems. (See pages 154 – 159)
Definition:
Mutually exclusive events:
Two events A and B are said to be mutually
exclusive (or disjoint) if
they cannot occur at the same time,
i.e.,
AB
.
4.2 Definitions of probability:
a)
Equally likely approach:
If an experiment has n(S) equally likely outcomes and
an event A has n(A) elements in it then P(A) = n(A) / N(S).
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
 Summer '08
 Kyung
 Statistics, Probability

Click to edit the document details