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)
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)