Stddev - Hutchinson encyclopedia article about Stddev Printer Friendly
Dictionary, Encyclopedia and Thesaurus - The Free Dictionary
3,578,599,115 visitors served.
forum Join the Word of the Day Mailing List For webmasters
?
Dictionary/
thesaurus
Medical
dictionary
Legal
dictionary
Financial
dictionary
Acronyms
 
Idioms
Encyclopedia
Wikipedia
encyclopedia
?

standard deviation
(redirected from Stddev)

    Also found in: Dictionary/thesaurus, Medical, Financial, Encyclopedia, Wikipedia 0.01 sec.

standard deviation

In statistics, a measure (symbol ςor s) of the spread of data. The deviation (difference) of each of the data items from the mean is found, and their values squared. The mean value of these squares is then calculated. The standard deviation is the square root of this mean.

If n is the number of items of data, x is the value of each item, and μ is the mean value, the standard deviation ςmay be given by the formula

where Σ indicates that the differences between the value of each item of data and the mean should be summed.

To simplify the calculations, the formula may be rearranged to

As a result, it becomes necessary only to calculate Σx and Σx2.

For example, if the ages of a set of children were 4, 4.5, 5, 5.5, 6, 7, 9, and 11, Σx would be 52, μ would be 52/n = 52/8 = 6.5, and Σx2 would be 378.5 (= 42 + 4.52 + 52 + 5.52 + 62 + 72 + 92 + 112).

Therefore, the standard deviation ςwould be
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
?Page tools
Printer friendly
Cite / link 		Feedback
?Sign in SSL protected
Email:
Password:
Register

Mentioned in?  References in periodicals archive?   Hutchinson browser?   Full browser?
 
The results for StdDev are shifted in contrast to MaxDist and higher convergence rates are reached (Figure 2(a)).
Stopping criteria for a constrained single-objective particle swarm ... by Zielinski, Karin; Laur, Rainer / Informatica
Retention, and Transfers of Critical Thinking in Experiment 1 Measures Effects Audio With Organizers A (n = 16) Mean Stddev Evaluations A+C vs.
Teaching critical thinking online by Astleitner, Hermann / Journal of Instructional Psychology
Firm risk is controlled for using the standard deviation of stock returns for the period 220 to 21 days prior to the announcement date, STDDEV, and by dummy variables for Moody's bond ratings A or higher, Baa, Ba, and B.
An explanation of underwriting spread differentials on complex ... by Becker, Michael W.; Long, Michael S. / Financial Management
 
 
 
Hutchinson Encyclopedia
?

Terms of Use | Privacy policy | Feedback | Copyright © 2012 Farlex, Inc.
Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.