First, find the mode, median, and mean of the given set of numbers.
Mode
The mode is the number that shows up frequently within the given set. In this case, it will be 10, as it shows up 4 times, 3 times more than any other number.
Mode: 10
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Median
The median is the number that is in the middle of the given set. In this case, there are 9 numbers, and so the 5th given number is your median:
10 , 10 , 10 , 10 , 11 , 12 , 13 , 15 , 17
Median: 11
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Mean
The mean is combining all numbers within the given set and dividing by the amount of numbers in that said set:
(10 + 10 + 10 + 10 + 11 + 12 + 13 + 15 + 17)/9 = 108/9 = 12
Mean: 12