CREATE TABLE table_27488 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "U.S. viewers  ( millions ) " TEXT, "Original U.S. air date" TEXT, "Prod. code" FLOAT)

How many U.S. viewers were there for the number 4 episode in season?
SELECT "U.S. viewers (millions)" FROM table_27488 WHERE "No. in season" = '4'
SELECT "U.S. viewers (millions)" FROM "table_27488" WHERE "No. in season" = '4'