A hygrometer is used to measure ……? A) Speed of sound B) Density of milk C) Humidity of air D) Specific gravity of liquids Related MCQs: ……. describes the events to which we measure what we purpose to measure? ……. Validity is the extent to which a tool appears to measure what it is supposed to measure? A type of criterion validity whereby a new measure correlates with a criterion measure taken at the same time is considered. The ability of a scale or measuring instrument to measure what it is intended to measure is called?