What is the median of the following numbers: 1, 3, 3, 6, 7, 8, 9?

To find the median of a set of numbers, you first need to arrange the numbers in numerical order, which is already done in this case: 1, 3, 3, 6, 7, 8, 9.

The median is the middle number in a sorted list. Since there are seven numbers in this list (an odd count), the median is simply the number in the fourth position. Counting to that position, we find:

1 (first) 3 (second) 3 (third) 6 (fourth) 7 (fifth) 8 (sixth) 9 (seventh)

The fourth number, which is the median, is 6. This means that half of the numbers in the list are lower than 6, and half are higher.

Thus, the correct answer is 6.