CREATE TABLE table_76527 ("Poll Source" TEXT, "Sample Size" FLOAT, "Margin of Error" FLOAT, "Date" TEXT, "Democrat" TEXT, "Republican" TEXT)

What is the sample size of the poll taken on Dec 13-15, 2007 that had a margin of error of more than 4 and resulted with Republican Mike Huckabee?
SELECT AVG("Sample Size") FROM table_76527 WHERE "Republican" = 'mike huckabee' AND "Margin of Error" > '4' AND "Date" = 'dec 13-15, 2007'
SELECT AVG("Sample Size") FROM "table_76527" WHERE "Date" = 'dec 13-15, 2007' AND "Margin of Error" > '4' AND "Republican" = 'mike huckabee'