CREATE TABLE table_47384 ("Poll Source" TEXT, "Dates administered" TEXT, "Democrat: Brian Schweitzer" TEXT, "Republican: Roy Brown" TEXT, "Libertarian: Stan Jones" TEXT, "Lead Margin" FLOAT)

What was the lead margin when Schweitzer had 55% and Jones had 2%?
SELECT SUM("Lead Margin") FROM table_47384 WHERE "Democrat: Brian Schweitzer" = '55%' AND "Libertarian: Stan Jones" = '2%'
SELECT SUM("Lead Margin") FROM "table_47384" WHERE "Democrat: Brian Schweitzer" = '55%' AND "Libertarian: Stan Jones" = '2%'