At 06:16 AM 8/21/01 -0700, RFerreira wrote:
>The formula wich gives the Standard Deviation ,
>SD=((x-mean)^2/(n-1))^0.5 ,can be applied to Any data set. When we
>have that value we know two things about the set: The Mean and the SD.
>With this two values We can have one powerful intuitive use to them:
>The "centre" of the set is the mean and 68% of values are in the
>interval [mean-SD to mean+SD], IF the set have Normal Distribution. If
>we forecast the set distribution is Not Normal What intuitive use have
>the values?
well, maybe the 68% values may not be totally relevant but, remember, the
SD is not just that ... but, a relative spread measure ... so, two
distributions that are not normal ... if one has an SD of 6 and the other
has an SD of 15 ...then the SD values still tell you something about the
spread of scores and variability
_________________________________________________________
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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