题解 | 牛牛的数学作业

def math():
    n = int(input())
    a = list(map(int, input().split()))
    resA = max(a) - min(a)
    mid = sum(a)/n
    resB = 0
    for i in a:
        resB += (i-mid)**2
    return f'{resA} {resB/n:.3f}'


t = int(input())
for i in range(0, t):
    print(math())