def getNum():
	nums = []
	iNumStr = input('请输入数字(回车退出):')
	while iNumStr != '':
		nums.append(eval(iNumStr))
		iNumStr = input('请输入数字(回车退出):')
	return nums

def mean(numbers):
	s = 0.0
	for i in numbers:
		s += i
	return s/len(numbers)
def dev(numbers, mean):
	sdev = 0.0
	for i in numbers:
		sdev += (i-mean)**2
	return pow(sdev/len(numbers), 0.5)
def median(numbers):
	sorted(numbers)
	size = len(numbers)
	if size%2 ==0:
		med = (numbers[size//2-1]+numbers[size//2])/2
	else:
		med = numbers[size//2]
	return med
n = getNum()
m = mean(n)
print('平均值:{},方差：{:.2f},中位数:{}'.format(m, dev(n,m),median(n)))
