To calculate the 5-number summary, range, standard deviation, and interquartile range (IQR) for the dataset: 5, 6, 6, 7, 7, 8, 8, 8, 9, 9, 14, 16, let's go through each step.
A. 5-Number Summary
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Minimum Value: The smallest number in the dataset.
- Minimum = 5
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Maximum Value: The largest number in the dataset.
- Maximum = 16
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Median (Q2): The middle value of the dataset when sorted. Since there are 12 values (even number), the median is the average of the 6th and 7th values.
- Median = (8 + 8) / 2 = 8
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Quartile 1 (Q1): The median of the first half of the data (the lower half: 5, 6, 6, 7, 7, 8). Again, since there are 6 values, Q1 is the average of the 3rd and 4th values.
- Q1 = (6 + 7) / 2 = 6.5
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Quartile 3 (Q3): The median of the second half of the data (the upper half: 8, 8, 9, 9, 14, 16). Q3 is the average of the 3rd and 4th values.
- Q3 = (9 + 9) / 2 = 9
5-Number Summary:
- Minimum Value = 5
- Maximum Value = 16
- Median (Q2) = 8
- Quartile 1 (Q1) = 6.5
- Quartile 3 (Q3) = 9
B. Additional calculations
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Range: The difference between the maximum and minimum values.
- Range = Maximum - Minimum = 16 - 5 = 11
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Interquartile Range (IQR): The difference between Q3 and Q1.
- IQR = Q3 - Q1 = 9 - 6.5 = 2.5
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Standard Deviation:
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First, find the mean:
- Mean = (5 + 6 + 6 + 7 + 7 + 8 + 8 + 8 + 9 + 9 + 14 + 16) / 12 = 8.25
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Then calculate the variance: \[ \text{Variance} = \frac{1}{n} \sum (x_i - \text{Mean})^2 \]
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Calculate each deviation squared:
- (5 - 8.25)² = 10.5625
- (6 - 8.25)² = 5.0625
- (6 - 8.25)² = 5.0625
- (7 - 8.25)² = 1.5625
- (7 - 8.25)² = 1.5625
- (8 - 8.25)² = 0.0625
- (8 - 8.25)² = 0.0625
- (8 - 8.25)² = 0.0625
- (9 - 8.25)² = 0.5625
- (9 - 8.25)² = 0.5625
- (14 - 8.25)² = 32.0625
- (16 - 8.25)² = 60.0625
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Total sum of squared deviations: = 10.5625 + 5.0625 + 5.0625 + 1.5625 + 1.5625 + 0.0625 + 0.0625 + 0.0625 + 0.5625 + 0.5625 + 32.0625 + 60.0625 = 117.5
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Variance = 117.5 / 12 ≈ 9.79
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Standard Deviation = √Variance ≈ √9.79 ≈ 3.13
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Summary of Results:
- Range = 11
- Standard Deviation ≈ 3.13
- Interquartile Range (IQR) = 2.5
Final Inputs:
Minimum Value = 5
Maximum Value = 16
Median (Q2) = 8
Quartile 1 (Q1) = 6.5
Quartile 3 (Q3) = 9
Range = 11
Standard Deviation = 3.13
Interquartile Range (IQR) = 2.5