Three readings are written down in this order: 9, 2 and 5. What is the median reading?

Erklärung

The readings must first be arranged by size as 2, 5 and 9, and the central position then holds 5, so the median is 5. Taking the middle entry of the list exactly as recorded gives 2, but the sequence in which readings happened to be written down has nothing to do with their ranking.