Capacity smaller than 3,292, and a Highest larger than 812, and a Stadium of strathclyde homes stadium has what sum of the average?
CREATE TABLE "stadia_and_attendances" (
  "team" text,
  "stadium" text,
  "capacity" real,
  "highest" real,
  "lowest" real,
  "average" real
);
SELECT SUM("average") FROM "stadia_and_attendances" WHERE "capacity"<'3,292' AND "highest">812 AND "stadium"='strathclyde homes stadium';