F-ratio or f-ratio may refer to:
* The F-ratio used in statistics, which relates the variances of independent samples; see
F-distribution
*
f-ratio (oceanography)
In oceanic biogeochemistry, the f-ratio is the fraction of total primary production fuelled by nitrate (as opposed to that fuelled by other nitrogen compounds such as ammonium). The ratio was originally defined by Richard Eppley and Bruce Pe ...
, which relates recycled and total primary production in the surface ocean
*
f-number, f-ratio, or focal ratio, the ratio of the focal length of an optical system to the diameter of its entrance pupil
See also
*
F-number (disambiguation) F-number or F number may refer to:
* f-number, the ratio of the lens's focal length to the diameter of the entrance pupil
*F number (chemistry) F number is a correlation number used in the analysis of polycyclic aromatic hydrocarbons (PAHs) as a de ...
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