Box Plot Girls
1. **Problem Statement:**
We are given a box plot summary for girls' times in seconds with the following data:
- A quarter of the girls took 32 seconds or less (lower quartile, $Q_1 = 32$).
- The fastest time was 26 seconds (minimum).
- A quarter of the girls took 43 seconds or more (upper quartile, $Q_3 = 43$).
- The slowest time was 50 seconds (maximum).
- The median time was 42 seconds ($Q_2 = 42$).
We need to find:
1. Upper quartile
2. Interquartile range
3. Median
4. Range
2. **Formulas and Important Rules:**
- The **upper quartile** ($Q_3$) is the value below which 75% of the data fall.
- The **interquartile range (IQR)** is the difference between the upper and lower quartiles: $$IQR = Q_3 - Q_1$$
- The **median** ($Q_2$) is the middle value of the data.
- The **range** is the difference between the maximum and minimum values: $$Range = Max - Min$$
3. **Calculations:**
- Upper quartile $Q_3 = 43$ seconds (given).
- Interquartile range $$IQR = Q_3 - Q_1 = 43 - 32 = 11$$ seconds.
- Median $Q_2 = 42$ seconds (given).
- Range $$Range = Max - Min = 50 - 26 = 24$$ seconds.
4. **Explanation:**
- The upper quartile is directly given as 43 seconds.
- The interquartile range measures the spread of the middle 50% of the data, calculated by subtracting the lower quartile from the upper quartile.
- The median is the middle value, given as 42 seconds.
- The range shows the total spread of the data from fastest to slowest times.
**Final answers:**
- Upper quartile: 43 seconds
- Interquartile range: 11 seconds
- Median: 42 seconds
- Range: 24 seconds