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Chapter 8: Discrete Probability Distributions
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Mean (Expected Value), Variance and Standard Deviation for a
Poisson Random Variable
The mean, variance, and the standard deviation of a Poisson random variable
can be computed using the following formulas.
Section Review
8-9 The Hypergeometric Probability Distribution
The hypergeometric distribution does not require the property of
independence for the trials and is based on the sampling being done without
replacement. Uses of the hypergeometric distribution are found in
acceptance sampling, electronic testing, quality assurance etc. Note, in these
tests, the items are usually destroyed and hence cannot be replaced in the
sample. Hence, sampling is done without replacement.
The Hypergeometric Experiment
:
In this experiment we will be interested
in the probability of selecting
successes from
items labeled as success
and
–
items from the
–
items labeled as failures when a sample of
n
is randomly selected from a population of size
.
Figure 8-25
depicts this
situation.
e-Self Review