Table: troy_ruttman_1950
Columns: year
entrant
chassis
engine
points

Question: What is the year with a Kurtis Kraft 500a chassis, and less than 1.5 points?
SQL: SELECT SUM("year") FROM troy_ruttman_1950 WHERE "chassis" = 'kurtis kraft 500a' AND "points" < 1.5

Question: What is the year with a kurtis kraft 500a chassis?
SQL: SELECT SUM("year") FROM troy_ruttman_1950 WHERE "chassis" = 'kurtis kraft 500a'