What is the median of the data set: {3, 7, 9, 5, 1}?

• A. 5
• B. 3
• C. 4
• D. 6

Answer: (A)

To find the median of a data set, the first step is to arrange the numbers in ascending order. In this case, the data set {3, 7, 9, 5, 1} is arranged as {1, 3, 5, 7, 9}.

The median is defined as the middle value in a sorted list. Since there are five numbers in this data set, which is an odd number, the median will be the value located at the third position—the middle number.

After sorting, the third number in the ordered list {1, 3, 5, 7, 9} is 5. Thus, the median of the data set is 5. This reflects the central tendency of the data, providing a measure of the middle point around which the other values are distributed.

The choice of 5 accurately represents this middle position in the sorted list, confirming its validity as the median.