Well, lets find the Median first. Putting the numbers in order from least to greatest (7,7,8,10,13,15,20) then count from each side to find the middle number (15). To find the Mean you will add all of the numbers together and divide by how many numbers there are so 7+7+8+10+13+15+20=80. We then do 80/7=11.4, rounded will be 11.0.
To find the mean you add up all the numbers and divide that amount by the amount of numbers. Which looks like this: 7 + 20 + 8 + 15 + 10 + 17 + 7 + 13= 97 97 divided by 8 = 12.125
The mean is 12.125.
To find the median you first need to put the numbers in order and then try to find the number in the middle. If there is two numbers in the middle those two numbers are still the median: 7, 7, 8, 10, 13, 15, 17, 20,