To find the interquartile range, we first need to find the lower quartile (Q1) and upper quartile (Q3).
1. Order the data set in ascending order: 2, 13, 14, 14, 15, 17, 18, 19
2. Find the median (middle value) of the lower half of the data set. The lower quartile (Q1) is the median of the lower half. In this case, the lower half is: 2, 13, 14, 14. So, Q1 = (13 + 14)/2 = 13.5
3. Find the median (middle value) of the upper half of the data set. The upper quartile (Q3) is the median of the upper half. In this case, the upper half is: 15, 17, 18, 19. So, Q3 = (17 + 18)/2 = 17.5
4. Finally, calculate the interquartile range (Q3 - Q1): 17.5 - 13.5 = 4.
Therefore, the interquartile range is 4.