Tools › Statistics › Descriptive and Outliers › Data Summary and Outliers › Example

Grubbs 1950: residuals of the semi-diameter of Venus (NIST 1.3.5.17.2)

ToolData Summary and Outliers
SourceGrubbs, F. E. (1950). "Sample Criteria for Testing Outlying Observations." Annals of Mathematical Statistics, Vol. 21, No. 1, pp. 27–58. Venus data, as reproduced in NIST/SEMATECH e-Handbook Section 1.3.5.17.2.
LevelUndergraduate

Problem

Fifteen residuals of Lieutenant Herndon's observations of the semi-diameter of Venus are −1.40, −0.44, −0.30, −0.24, −0.22, −0.13, −0.05, 0.06, 0.10, 0.18, 0.20, 0.39, 0.48, 0.63 and 1.01. Is the value −1.40 an outlier at the 5 % level?

Inputs to Enter

  • One column of the fifteen residuals; outlier level α = 0.05
Open the Data Summary and Outliers tool

Answers

  • Grubbs G = 2.5737 at −1.40 against the two-sided 5 % critical value 2.5483: −1.40 is flagged
  • Tukey inner fence −1.0175 with one value outside; generalized ESD finds 1 outlier

Notes

Paste the fifteen values in place of the default columns.

More Examples for This Tool