query: SELECT avg(enrollment) FROM university WHERE founded  <  1850
question: What are that average enrollment size of the universities where are founded them before 1850?
query_toks: SELECT avg ( enrollment ) FROM university WHERE founded < 1850
query_toks_no_value: select avg ( enrollment ) from university where founded < value
question_toks: What are that average enrollment size of the universities where are founded them before 1850?