Let x be the median of the data 13, 8, 15, 14, 17, 9, 14, 16, 13, 17, 14, 15, 16, 15, 14. If 8 is replaced by 18, then the median of the data is y. What is the sum of the values of x and y?

Arranging data in ascending order: 8, 9, 13, 13, 14, 14, 14, 14, 15, 15, 15, 16, 16, 17, 17. With 15 values, median is the 8th value = 14, so x = 14. After replacing 8 with 18: 9, 13, 13, 14, 14, 14, 14, 15, 15, 15, 16, 16, 17, 17, 18. Median = 8th value = 15, so y = 15. Therefore x + y = 14 + 15 = 29.