题解 | 牛牛的数学作业

n=int(input())
for i in range(n):
    a=int(input())
    b=list(map(int,input().split()))
    jicha=max(b)-min(b)
    p=sum(b)/a
    f=0
    for j in range(a):
        he=(b[j]-p)**2
        f=f+he
    fang=f/a
    print(f"{jicha} {fang:.3f}")