What is the ERP W for the station whose call sign is K248BJ and whose frequency MHz is higher than 97.5?
CREATE TABLE "broadcast_translators_of_kjjj" (
  "call_sign" text,
  "frequency_m_hz" real,
  "city_of_license" text,
  "erp_w" real,
  "class" text,
  "fcc_info" text
);
SELECT AVG("erp_w") FROM "broadcast_translators_of_kjjj" WHERE "call_sign"='k248bj' AND "frequency_m_hz">97.5;