Premium
STATISTICAL BRIEFING: STATISTICAL POWER
Author(s) -
LAMB CHRISTOPHER R.
Publication year - 2009
Publication title -
veterinary radiology and ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.541
H-Index - 60
eISSN - 1740-8261
pISSN - 1058-8183
DOI - 10.1111/j.1740-8261.2009.01546.x
Subject(s) - power (physics) , medicine , citation , library science , reprint , computer science , physics , quantum mechanics , astronomy
STATISTICAL POWER IS the probability that a statistical test will indicate a significant difference when there truly is one. The power of a statistical test is analogous to the sensitivity of a diagnostic test. Just as obtaining a negative result for a sensitive diagnostic test can be used to rule out a diagnosis, a negative result for a powerful statistical test allows us to be sure that no difference exists. Knowing the statistical power of a study becomes particularly important when the result of a study is negative because there is a need to distinguish a true negative result (i.e., there really is no difference) from a false negative result (i.e., there is an underlying difference, but the study was not powerful enough to find it). Adequate power of a statistical test is usually considered to be 0.8. This means there is an 80% chance of detecting a difference if one exists.