statistician vs reckoner

statistician and reckoner both are nouns.

Word	Noun	Adjective	Verb	Adverb
statistician	Yes	No	No	No
reckoner	Yes	No	No	No

As nouns, reckoner is a hypernym of statistician; that is, reckoner is a word with a broader meaning than statistician:

statistician: someone versed in the collection and interpretation of numerical data (especially someone who uses statistics to calculate insurance premiums)
reckoner: an expert at calculation (or at operating calculating machines)

Other hypernyms of statistician include calculator, computer, estimator, figurer.

statistician (noun)	reckoner (noun)
someone versed in the collection and interpretation of numerical data (especially someone who uses statistics to calculate insurance premiums)	a handbook of tables used to facilitate computation
a mathematician who specializes in statistics	an expert at calculation (or at operating calculating machines)