Given a data set with outliers, which measure of central tendency is least affected by extreme values?

• A. Mean
• B. Mode
• C. Range
• D. Median

Answer: (D)

Outliers don’t pull the center as hard when you look at the data in order. The median is the middle value when data are sorted, so extreme numbers at the high or low end don’t change that middle position unless they actually alter how many values lie on each side. That makes the median robust to extreme values. In contrast, the mean adds up all values, so a single very large (or very small) outlier shifts the average noticeably. The mode depends on the most frequent value and can be sensitive to distribution shape, while the range simply measures spread, not central tendency. So the middle value remains the least affected by outliers.