Orbital - Vol. 12 No. 2 - April-June 2020

The Paradox of Precision

André F. Oliveira
Universidade Federal de Viçosa
Astrea F. S. Silva
Universidade Federal de Viçosa
Maria Eliana L. R. Queiroz
Universidade Federal de Viçosa
Antônio Augusto Neves
Universidade Federal de Viçosa
Published June 29, 2020
  • standard deviation,
  • global variance,
  • precision of measurements,
  • error propagation
How to Cite
Oliveira, A. F.; Silva, A. F. S.; Queiroz, M. E. L. R.; Neves, A. A. The Paradox of Precision. Orbital: Electron. J. Chem. 2020, 12, 105-107.


This paper is about a typical mistake in the calculation of standard deviation of measurements in cases in which there are no differences among repetitious replicates. Some students believe the standard deviation in those case is equal to zero. So, this mistake leaves to a paradox: worse balance should show better results (i.e. standard deviation equal to zero). The solution of this simple, but important situation is shown.

DOI: http://dx.doi.org/10.17807/orbital.v12i2.1466