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Section 4.1
Random Variable
A
random variable x
represents a numerical value associated
with each outcome of a probability experiment.
•
A random variable is
discrete
if it has a finite or
countable number of possible outcomes that can be
listed.
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A random variable is
continuous
if it has an
uncountable number of possible outcomes,
represented by an interval on the number line.
Discrete Probability Distribution
A
discrete probability distribution
list each possible value the
random variable can assume, together with its probability. A
Probability distribution must satisfy the following conditions.
IN WORDS
1.
The probability of each value of the discrete random
variable is between 0 and 1, inclusive.
In Symbols
0
P (x)
1
≤
≤
2.
The sum of all the probabilities is 1.
In symbols
P (x) = 1
∑
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View Full Document P(x) = f/∑
Guidelines for Constructing a Discrete Probability Distribution
Let X be a discrete random variable with possible outcomes
,
,…,
.
x1 x2
xn
1.
Make a frequency distribution for the possible outcome
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This note was uploaded on 02/03/2011 for the course ACCT 1100 taught by Professor Matter during the Spring '08 term at Metropolitan Community College Omaha.
 Spring '08
 MATTER

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