arithmetic mean vs expectation

arithmetic mean and expectation both are nouns.

Word	Noun	Adjective	Verb	Adverb
arithmetic mean	Yes	No	No	No
expectation	Yes	No	No	No

As nouns, arithmetic mean and expectation are synonyms defined as:

arithmetic mean and expectation: the sum of the values of a random variable divided by the number of values

Other synonyms of arithmetic mean include expected value, first moment.

arithmetic mean (noun)	expectation (noun)
the sum of the values of a random variable divided by the number of values	belief about (or mental picture of) the future
	the sum of the values of a random variable divided by the number of values
	the feeling that something is about to happen
	anticipating with confidence of fulfillment