STATISTICS 2  BASIC PROBABILITY
o
A random experiment
is a process of making an observation or a measurement (called an outcome
) in
which the outcome cannot be predicted in advance with complete certainty.
Therefore, we assign a
probability (likelihood of occurrence) to each of the possible outcomes or groupings of outcomes.
o
Sample Space (
S
)
is the set of all possible outcomes for a random experiment.
o
An event
is any subcollection of outcomes; it is simply a subset of the sample space.
The event
A
is said
to “occur” if the outcome falls in the set
A
.
So each time an outcome is observed, a given event
A
either
occurs or does not occur.
o
P(A)
= the probability of the event
A
= the longrun relative frequency of occurrence of the event
A
= the
proportion or fraction of times that the event
A
occurs in a large number of independent repeated trials of
the experiment.
(Another type of probability is based on a subjective assessment instead of on data.)
The simplest rules of probability
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 Spring '08
 sugahara
 Statistics, Probability, Probability distribution, Probability theory

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