The interquartile range of the data set is 4.2, 2, 3, 3, 4, 5, 5, 6, 7, 9, 12Which explains whether or not 12 is an outlier?

The data have an upper quartile of 7 and an interquartile range of 4. The upper outlier fence is Q3 + 1.5 × IQR = 7 + 1.5 × 4 = 7 + 6 = 13. Since 12 is less than 13, it is not an outlier; this matches choice D.

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