CREATE TABLE "table1_25740548_4" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text,
  "u_s_viewers_million" text
);

Question: Who directed the episode with production code ca311?
SQL: SELECT "directed_by" FROM "table1_25740548_4" WHERE "production_code"='CA311';

Question: What is the series episode number of the episode titled "sound and vision"?
SQL: SELECT MAX("series_num") FROM "table1_25740548_4" WHERE "title"='\"Sound and Vision\"';

Question: Which episode had 2.75 million viewers in the U.S.?
SQL: SELECT "title" FROM "table1_25740548_4" WHERE "u_s_viewers_million"='2.75';

Question: Who directed the episode with production code ca303?
SQL: SELECT "directed_by" FROM "table1_25740548_4" WHERE "production_code"='CA303';