In article <X9-dnYiwhco8c8XPnZ2dnUVZ_oWdnZ2d@giganews.com>, fom <fomJUNK@nyms.net> wrote:
> On 10/11/2013 11:56 PM, Christiano wrote: > > Why in the formula of standard deviation uses squares instead of simply > > putting differences within module? > > > > Example: > > standard deviation² = Sum[(y-ym)²]/(n-1) > > > > Is not it better this? > > standard deviation = Sum[|y-ym|]/(n-1)
This one, or rather Sum[|y-ym|]/n, is more commonly called the mean absolute deviation rather than standard deviation.