Answer:
The program in Python is as follows:
mynum = []
num = int(input("Enter a number: "))
total = 0
while num >= 0:
  mynum.append(num)
  total+=num
  num = int(input("Enter a number: "))
 Â
print("Smallest: ",min(mynum))
print("Largest: ",max(mynum))
print("Average: ",total/len(mynum))
Explanation:
This creates an empty list
mynum = []
This prompts the user for input
num = int(input("Enter a number: "))
This initializes total to 0
total = 0
The following is repeated until a negative number is inputted
while num >= 0:
This appends the inputted number into the list
  mynum.append(num)
This calculates the sum of all the numbers inputted
  total+=num
This prompts the user for another input
  num = int(input("Enter a number: "))
 Â
This calculates and prints the smallest
print("Smallest: ",min(mynum))
This calculates and prints the largest
print("Largest: ",max(mynum))
This calculates and prints the average
print("Average: ",total/len(mynum))