def median(l: list):
    l = sorted(l)
    if len(l) % 2 == 1:
        return l[len(l) // 2]
    else:
        return (l[len(l) // 2 - 1] + l[len(l) // 2]) / 2.0
from typing import List
def mean_absolute_deviation(numbers: List[float]) -> float:
    mean = sum(numbers) / len(numbers)
    return sum(abs(x - mean) for x in numbers) / len(numbers)