To determine what the Interquartile Range (IQR) indicates about the dataset, let's first calculate the IQR.
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Arrange the scores in ascending order:
- 287, 287, 290, 295, 329, 365, 387, 389, 397
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Find the median (Q2):
- The median score (Q2) is the middle value. With 9 scores, the middle one is the 5th score:
- Median (Q2) = 329
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Find the first quartile (Q1):
- Q1 is the median of the first half of the data (the first four scores):
- 287, 287, 290, 295
- The median here is the average of 287 and 290:
- Q1 = (287 + 290) / 2 = 288.5
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Find the third quartile (Q3):
- Q3 is the median of the second half of the data (the last four scores):
- 365, 387, 389, 397
- The median here is the average of 387 and 389:
- Q3 = (387 + 389) / 2 = 388
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Calculate the IQR:
- IQR = Q3 - Q1 = 388 - 288.5 = 99.5
Now, assessing what the IQR indicates about the dataset:
- An IQR of 99.5 indicates the range of the middle 50% of the scores. It measures the spread of the central half of the data values.
- A higher IQR would suggest a larger variability among the middle scores.
Given the options provided, the correct interpretation is:
An IQR of 99.5 indicates that the video game player had a relatively large variability for their middle scores.