CREATE TABLE table_78734 ("Date" TEXT, "Airline" TEXT, "Aircraft type" TEXT, "Registration" TEXT, "People on board" FLOAT, "Fatalities" FLOAT)

How many fatalities are there for the airline of spantax, with a registration of ec-arz?
SELECT AVG("Fatalities") FROM table_78734 WHERE "Airline" = 'spantax' AND "Registration" = 'ec-arz'
SELECT AVG("Fatalities") FROM "table_78734" WHERE "Airline" = 'spantax' AND "Registration" = 'ec-arz'