如何始终获得正输出？

这是我的代码：

import random
minimum=int(input("Enter minimum value: "))
maximum=int(input("Enter maximum value: "))
if minimum>maximum:
    temp=minimum
    minimum=maximum
    maximum=temp
howMany = int(input("How many numbers do you want to generate?"))
sum=0
n=1
while n<=howMany:
    num=random.randrange(minimum,maximum)
    sum+=num
    n+=1
    print("Your random generated number is",num)
print("Python's random average between", minimum, "and", maximum, "is", sum/howMany)
avg=minimum+maximum/2
avgTwo=sum/howMany
difference=avgTwo-avg
print("The actual average of minimum and maximum is", avg)
print("The difference from the calculated average and from the actual average is", difference)

在计算差异时，我需要始终获得一个正数。我尝试翻转要减去的变量，但在随机时间收到一个负数。