98f655069e809f55a1c6bd57f7fcc16c769c92fa.doc
STATISTICS 301—APPLIED STATISTICS,
Statistics for Engineers and Scientists, Walpole, Myers, Myers, and Ye, Prentice Hall
Goal:
In this section we will tackle the concept of
RANDOM VARIABLES
, an important concept in statistics.
Defn
: A
random variable (RV)
is a
method of assigning
one and only one number
to the outcome
of an
experiment.
Notation
:
Upper Case
Latin letters
are used to
denote random variable
, eg X, or Y, or F.
Lower case
Latin letters
are used to
denote the VALUE of the RV
, eg x’s, y’s, f’s and are listed in the sample
space
of the RV.
SOME EXAMPLES
1.
Experiment consists of rolling a die (fair or otherwise)
D = # dots on the top face
S
D
= { 1, 2, 3, 4, 5, 6 }
2.
Experiment consists of tossing a fair coin
H = # heads
S
H
= { 0, 1 }
3.
Experiment consists of selecting a student randomly from class
ID = Miami ID/Banner ID
S
ID
= { 00123456, 00123457, … }
4.
Experiment consists of selecting a student randomly from class
A = age (in years)
S
A
= { 21, 22, …
}
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4/28/2011
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