如何用python计算基本统计值？

def getNum(): #从控制台获取多个不确定数据的方法

    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):#计算平均值

    s = 0.0;

    for num in numbers:

        s = s + num;

    return s/len(numbers);

def dev(numbers, mean):#计算方差

    sdev = 0.0;

    for num in numbers:

        sdev = sdev + (num - mean)**2;

    return pow(sdev/(len(numbers)-1), 0.5);

def median(numbers):#计算中位数

    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)));

#运行结果

#请输入数字(回车退出):10

#请输入数字(回车退出):20

#请输入数字(回车退出):30

#请输入数字(回车退出):

#平均值:20.0,方差:10.00,中位数:20.