Name the total number of written by for original air date for may 8, 2005
CREATE TABLE "table1_1876825_7" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text
);
SELECT COUNT("written_by") FROM "table1_1876825_7" WHERE "original_air_date"='May 8, 2005';