Influential observation

In Anscombe's quartet the two datasets on the bottom both contain influential points. All four sets are identical when examined using simple summary statistics, but vary considerably when graphed. If one point is removed, the line would look very different.

In statistics, an influential observation is an observation for a statistical calculation whose deletion from the dataset would noticeably change the result of the calculation.[1] In particular, in regression analysis an influential observation is one whose deletion has a large effect on the parameter estimates.[2]

  1. ^ Burt, James E.; Barber, Gerald M.; Rigby, David L. (2009), Elementary Statistics for Geographers, Guilford Press, p. 513, ISBN 9781572304840.
  2. ^ Cite error: The named reference Everitt was invoked but never defined (see the help page).