mean deviation from the mean vs mean deviation

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

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

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

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

mean deviation from the mean (noun)	mean deviation (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