cases = int(input())

for i in range(cases):
    try:
        nl = int(raw_input())
    except ValueError:
        pass
    candy = []
    num_children = int(input())
    for i in range(num_children):
        num = int(raw_input())
        candy.append(num)
    all = sum(candy)
    if all % num_children == 0:
        print "YES"
    else:
        print "NO"