What is the population when the  Per capita income of $18,884, and a Number of households smaller than 14,485?
CREATE TABLE "mississippi_counties_ranked_by_per_capit" (
  "county" text,
  "per_capita_income" text,
  "median_household_income" text,
  "population" real,
  "number_of_households" real
);
SELECT SUM("population") FROM "mississippi_counties_ranked_by_per_capit" WHERE "per_capita_income"='$18,884' AND "number_of_households"<'14,485';