Five Number Summary D0B602
1. **State the problem:** We are given a stem-and-leaf plot and need to find the five number summary: minimum, lower quartile (Q1), median (Q2), upper quartile (Q3), and maximum.
2. **List the data points:** From the stem-and-leaf plot:
- 7 | 0 2 3 7 8 9 corresponds to 70, 72, 73, 77, 78, 79
- 8 | 1 5 6 9 corresponds to 81, 85, 86, 89
- 9 | 0 1 2 2 6 6 6 6 7 8 corresponds to 90, 91, 92, 92, 96, 96, 96, 96, 97, 98
3. **Order the data:** The data in ascending order is:
$$70, 72, 73, 77, 78, 79, 81, 85, 86, 89, 90, 91, 92, 92, 96, 96, 96, 96, 97, 98$$
4. **Count the data points:** There are 20 data points.
5. **Find the minimum and maximum:** Given as 70 and 98.
6. **Find the median (Q2):** Since there are 20 points (even number), median is average of 10th and 11th values.
- 10th value: 89
- 11th value: 90
$$\text{Median} = \frac{89 + 90}{2} = 89.5$$
7. **Find the lower quartile (Q1):** Median of the lower half (first 10 values):
$$70, 72, 73, 77, 78, 79, 81, 85, 86, 89$$
Median of these 10 values is average of 5th and 6th:
- 5th: 78
- 6th: 79
$$Q1 = \frac{78 + 79}{2} = 78.5$$
8. **Find the upper quartile (Q3):** Median of the upper half (last 10 values):
$$90, 91, 92, 92, 96, 96, 96, 96, 97, 98$$
Median is average of 5th and 6th:
- 5th: 96
- 6th: 96
$$Q3 = \frac{96 + 96}{2} = 96$$
**Final five number summary:**
- Minimum: 70
- Lower quartile (Q1): 78.5
- Median (Q2): 89.5
- Upper quartile (Q3): 96
- Maximum: 98