import sys
from math import sqrt, pi, sin
inp = lambda : sys.stdin.readline()[:-1]
mii = lambda x = " ": [*map(int,input().split(x))]
mfi = lambda x = " ": [*map(float,input().split(x))]
ii = lambda : int(input())
for _ in range(ii()):
n = int(input())
l = mii()
k = (max(l) +min(l)) / 2
k2 = sum(l) / n
print("Yes" if abs(k - k2) < 1 else "No")