The ages of eight cousins at a family gathering are 13, 17, 11, 20, 15, 22, 14 and 19 years. The eldest cousin goes home early. What is the median age of the seven who are left?

Put the ages in order: 11, 13, 14, 15, 17, 19, 20, 22. With eight values the median was the mean of the 4th and 5th, (15 + 17)/2 = 16. Once 22 leaves, seven ages remain — 11, 13, 14, 15, 17, 19, 20 — and with an odd count the median is the single 4th value, 15. Quoting 16 answers the question before the cousin left; 17 keeps averaging two middle values when the count has turned odd; and 14 is the 3rd value.