The median weight is the value that divide the sample of wights into a higer half and a lower half.
To find the median wight, first we must put the weights in crescent order:
9, 9, 9, 10, 13, 14, 15
Then, we can check that 10 pounds is the median weight, since there is three lower weights on its left {9,9,9} and three higer weights on its right {13, 14, 15}
Finally, the mean is caculated by the sum of the weights of each cat divided by the total number of cats:
