To determine the mode of the given data set, we first need to identify which number appears most frequently. The data set provided is: 8, 11, 20, 10, 2, 17, 15, 5, 16, 15, 25, 6.
Next, let’s count how many times each number appears:
- 8 appears 1 time
- 11 appears 1 time
- 20 appears 1 time
- 10 appears 1 time
- 2 appears 1 time
- 17 appears 1 time
- 15 appears 2 times
- 5 appears 1 time
- 16 appears 1 time
- 25 appears 1 time
- 6 appears 1 time
From this count, we see that the number 15 is the only number that appears more than once, specifically two times.
Therefore, the mode of this data set is 15, as it is the most frequent value.