If I recall, names ending in "i" are usually Polish and those in "y" are russian or feminine.
I’m not a student of Russian or Polish, but my husband’s (decidedly Polish on both sides) last name ends in “y”. From genealogical research I’ve learned that if a Polish woman was first in line when his ancestors arrived at Ellis Island it could’ve ended with an ‘a’. At this point though for immigrants who came over when they still passed through Ellis Island the spellings are too numerous for any hard and fast rules. I have been told that our last name is actually a Russian word, so again, who knows!! LOL