The median annual income for heads of household in a certain city is $18,000.?

Question

Four such heads of households are randomly selected for inclusion in an opinion poll.

Find the probability distribution of X, the number (out of the four) who have annual incomes below $18,000.

Answer 1

A median income means 1/2 of all households are above the value, 1/2 below. Thats 50/50, or 0.5

Looks like a standard binomial distribution to me.