Median of a List

The median is the value sitting in the middle once the numbers are lined up in order. Half the list is below it, half above.

Task: write median(values) returning that middle value, rounded to 4 decimal places.

The two cases you have to handle:

• An odd number of values has one true middle — line them up and take it.
• An even number of values has no single middle, so take the average of the two middle values. For [2, 4, 7, 9] that's (4 + 7) / 2 = 5.5.

Also worth knowing:

• values is never empty, and it arrives in no particular order — sort it yourself first, or "the middle" means nothing.
• Work the position out from the list's length rather than reaching for statistics.median; the point is to see how the two cases differ.

The median only cares about position, never size — so a wildly large value at the end barely moves it.