Explanation

To find the median of a set of numbers, you arrange the numbers in ascending order and then find the middle number. If the number of observations is odd, the median is the middle number. If the number of observations is even, the median is the average of the two middle numbers.

Arranging the numbers in ascending order: 1, 2, 3, 4, 5, 6

Since there are 6 observations (an even number), the median is the average of the two middle numbers, which are the 3rd and 4th numbers: 3 and 4.

So, the median of the set is the average of 3 and 4, which is 3.5.