The numbers in order are
3, 4, 4, 4, 5, 6, 6, 6, 8
The median is the number in the middle, which is 5.
The range is the largest number minus the smallest number, 8 - 3 = 5
The mean is the sum of all the numbers divided by how many number are the in the list, 3 + 4 + 4 + 4 + 5 + 6 + 6 + 6 + 8 = 46, 46/9 = 5.11