mean deviation vs mean deviation from the mean

mean deviation and mean deviation from the mean both are nouns.

Word	Noun	Adjective	Verb	Adverb
mean deviation	Yes	No	No	No
mean deviation from the mean	Yes	No	No	No

As nouns, mean deviation and mean deviation from the mean are synonyms defined as:

mean deviation and mean deviation from the mean: the arithmetic mean of the absolute values of deviations from the mean of a distribution

mean deviation (noun)	mean deviation from the mean (noun)
the arithmetic mean of the absolute values of deviations from the mean of a distribution	the arithmetic mean of the absolute values of deviations from the mean of a distribution