1. **State the problem:** We have a data set representing the number of pets owned by people: $0, 3, 6, 9, 12, 15$. We need to find: a) The least number of pets owned. b) The median number of pets. c) The interquartile range (IQR). 2. **Important definitions and formulas:** - The least number (minimum) is the smallest value in the data set. - The median is the middle value when the data is ordered. For an even number of data points, it is the average of the two middle numbers. - The interquartile range (IQR) is the difference between the upper quartile (Q3) and the lower quartile (Q1): $$\text{IQR} = Q_3 - Q_1$$ 3. **Find the least number of pets:** The data set ordered is already: $0, 3, 6, 9, 12, 15$ The least number is the first value: $$\boxed{0}$$ 4. **Find the median:** Number of data points $n=6$ (even). Median is the average of the 3rd and 4th values: $$\text{Median} = \frac{6 + 9}{2} = \frac{15}{2} = 7.5$$ 5. **Find the interquartile range (IQR):** From the box plot, lower quartile $Q_1 = 3$, upper quartile $Q_3 = 9$. Calculate: $$\text{IQR} = 9 - 3 = 6$$ **Final answers:** a) Least number of pets: $0$ b) Median number of pets: $7.5$ c) Interquartile range: $6$