Continuous random variable
measured (not counted)
takes any value within a given interval
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Continuous Probability Distribution
The distribution of a continuous random variable
No gaps within the interval
Normal Distribution
Bell-shaped
Symmetrical
Mean=median=mode
Location is determined by the mean, μ
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Spread is determined by the standard deviation, Ï
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The random variable has an infinite theoretical range:
to +
The formula for the normal probability density function:
Where
X = any value of the continuous variable
μ = the population mean
Ï = the population standard deviation
e = the mathematical constant approximated by 2.71828
Ï = the mathematical constant approximated by 3.14159
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A normal distribution with
a mean of zero, and
a standard deviation of one
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