Here's a more human-friendly version:
1. Arrange the numbers in order: 1, 1, 4, 6, 7, 9
2. Find the middle value, which is the median (Q2): (4 + 6) / 2 = 5
3. Calculate Q1 (the median of the lower half): For 1, 1, 4, the median is 1
4. Calculate Q3 (the median of the upper half): For 6, 7, 9, the median is 7
5. Finally, find the quartile range by subtracting Q1 from Q3: 7 - 1 = 6
So, the quartile range for this dataset is 6.
