What is the average MHz Frequency of radio rezonans?
CREATE TABLE "analogue_radio_programmes" (
  "program" text,
  "frequency_m_hz" real,
  "erp_k_w" real,
  "polarisation" text,
  "antenna_diagram_around_nd_directional_d" text
);
SELECT AVG("frequency_m_hz") FROM "analogue_radio_programmes" WHERE "program"='radio rezonans';