Which value is referred to as the median of a data set?

The median of a data set is defined as the middle value when the values are arranged in ascending or descending order. This statistical measure is particularly useful because it effectively represents the center of a data set by dividing it into two equal halves, regardless of how the values are distributed. If the number of observations is odd, the median is the middle number. If the number of observations is even, the median is calculated by taking the average of the two middle numbers.

This characteristic makes the median a robust measure of central tendency, especially suitable for data sets with outliers or skewed distributions, as it is not influenced by extreme values. Hence, identifying the median involves first sorting the data, which directly aligns with the option that defines the median as the middle value when sorted.