If you have a set like (1, 1, 2, 4, 5, 5, 7) then there are two modes, 1 and 5, because they appear the joint-most amount of times.
But if you have a set like (1, 3, 6, 9, 14, 29) then there are no modes, because they all appear the same amount of times.
The median's feeling left out, so I'll put him in.
The median is the middle in a set of numbers when they are arranged in order.
Using justlooking's set, that would be 2. If she had put them like (2, 4, 1, 6, 2) then you would have to arrange them in order first.