Question 7 • Concepts in Probability and Statistics
Sort the data: 104, 109, 115, 118, 120, 135, 139, 141, 148. The middle value is 120, so the median is 120; the lower and upper halves have medians of (109 + 115) ÷ 2 = 112 and (139 + 141) ÷ 2 = 140. Thus, the interquartile range is 140 − 112 = 28. There are no outliers: the usual 1.5 × IQR fences are 70 and 182, and every value falls within them.
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