To find the 5-number summary (minimum, first quartile, median, third quartile, and maximum) for the given data, we'll follow these steps:
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Sort the Data: The data is already sorted in ascending order:
1.0, 1.0, 1.5, 2.0, 3.0, 3.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.5, 4.5, 5.0, 5.0, 5.0, 6.0, 6.5, 7.5, 8.0
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Determine the Minimum and Maximum:
- Minimum: 1.0
- Maximum: 8.0
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Calculate the Median (Q2):
- There are 20 data points (even number), so the median will be the average of the 10th and 11th values.
- 10th value: 4.0
- 11th value: 4.0
- Median (Q2) = (4.0 + 4.0) / 2 = 4.0
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Calculate the First Quartile (Q1):
- Q1 is the median of the first half of the data (the 1st to the 10th values).
- First half: 1.0, 1.0, 1.5, 2.0, 3.0, 3.0, 4.0, 4.0, 4.0, 4.0
- Since there are 10 values in the first half (even), Q1 is the average of the 5th and 6th values.
- 5th value: 3.0
- 6th value: 3.0
- Q1 = (3.0 + 3.0) / 2 = 3.0
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Calculate the Third Quartile (Q3):
- Q3 is the median of the second half of the data (the 11th to the 20th values).
- Second half: 4.5, 5.0, 5.0, 5.0, 6.0, 6.5, 7.5, 8.0
- Since there are 10 values in the second half (even), Q3 is the average of the 5th and 6th values.
- 5th value: 6.0
- 6th value: 6.5
- Q3 = (6.0 + 6.5) / 2 = 6.25
Now, compiling this information, the 5-number summary is:
- Minimum: 1.0
- Q1: 3.0
- Median (Q2): 4.0
- Q3: 6.25
- Maximum: 8.0
Thus, the final 5-number summary can be written as:
The 5-number summary is
1.0,
3.0,
4.0,
6.25,
8.0.