What was the sample size for polling on May 2-7, 2007 for Hillary Clinton?
CREATE TABLE "connecticut" (
  "poll_source" text,
  "sample_size" real,
  "margin_of_error" real,
  "date" text,
  "democrat" text,
  "republican" text
);
SELECT "sample_size" FROM "connecticut" WHERE "date"='may 2-7, 2007' AND "democrat"='hillary clinton';