Volume Limited Sample?

[Zaphodx57x]

Does anybody have a link to a precise definition of a "volume limited sample." This pertains especially to sky surveys that catalog galaxies. Due to limited precision, surveys tend to miss fainter galaxies as redshift increases. Thus, very loosely, I think, a volume limited sample filters out certain galaxies so that only galaxies of a finite brightness range are considered at all pertinent redshifts. However, I am looking for a precise definition, but can't seem to find one.

[matt.o]

A volume limited sample just takes galaxies within a certain redshift range.

Thus, very loosely, I think, a volume limited sample filters out certain galaxies so that only galaxies of a finite brightness range are considered at all pertinent redshifts.

Do you mean absolute or apparent brightness? If the latter, this is not a volume limited sample.