#CalStatistics.py
def getNum():
    num=[]
    iNumStr=input("请输入数字:（回车退出）")
    while iNumStr !="":
        num.append(eval(iNumStr))
        iNumStr= input("请输入数字:（回车退出）")
    return num

def means(numbers):
    s=0.0
    for num in numbers:
        s+=num
    return s/len(numbers)

def dev(numbers,mean):
    sdev=0
    for num in numbers:
        sdev+=pow(num-mean,2)
    return pow(sdev/(len(numbers)-1),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=means(n)
print("平均值：{} 方差：{:.2f} 中位数：{}".format(m,dev(n,m),median(n)))
