Answer: IQR = 0.5
first we’ll put the data set in ascending order:
81, 82, 83, 83, 84, 84, 84, 85
Then find the median (middle number) since there are two, 83 and 84, we average them: 83.5
The first quartile is the middle number of the bottom half of the data set (bottom half = 81, 82, 83, 83) again, we’ll average, so 82.5
The third quartile is the middle number of the top half of the data set. (Top half = 84, 84, 84, 85) So third quartile is 84.
IQR is the difference between the first and third quartiles. 84 - 83.5 = 0.5
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