A collection of some tests commonly used for identifying outliers:

  - Chi-squared test for outlier
  - Test for outlying or inlying variance
  - Dixon tests for outlier
  - Grubbs tests for one or two outliers in data sample
  - Find value with largest difference from the mean
  - Critical values and p-values for Cochran outlying variance test
  - Critical values and p-values for Dixon test
  - Calculate critical values and p-values for Grubbs test
  - Interpolate tabularized distribution
  - Remove the value(s) most differing from the mean
  - Calculate scores of the sample

WWW: http://cran.r-project.org/web/packages/outliers/