Home > Statistics Every Writer Should Know > The Stats Board > Discusssion
population and sample standard deviations
Message posted by Steve Mardekian on February 14, 2000 at 12:00 AM (ET)
I have a question. I know
there are two different types
of standard deviations-
population and sample. How do
you know when to use which? Is
it true that population should
only be used when n is greater
than or equal to 30? Please
help me.
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Re: population and sample standard deviations
Message posted by Vern Myers on February 17, 2000 at 12:00 AM (ET)
Population standard deviation ("n" in the denominator)should be used to determine the standard deviation of the population where one has measurements on every item in the population. Sample standard deviation ("n-1" in the denominator) is used to estimate the population standard deviation from a sample taken from the population.
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