(n) :
the
measure of central tendency of a set of values computed by
ordering the values and taking the value at position ( + 1) / 2 when is odd or the
arithmetic mean of the values at positions / 2 and ( / 2) + 1 when is even; the area separating two lanes of opposite-direction traffic in the United States. This area is often covered with
vegetation, but also may be covered in concrete and possess
traffic accident safety devices such as
guardrails