math
posted by Not Sure on .
Given the following values, which number would be considered an outlier?
0.9, 2.1, 3.2, 3.9, 7.4, 5.8, 7.2, 8, 9.1
2.1
9.1
8
7.4
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I'm not sure because I was taught that an outlier is either too high or too low so it doesn't fit in the data.

well, since the mean is 5.3, I'd go with 0.9, but as that's not a choice, the only selection left is 9.1, but it's not much of an outlier.

Weird... I got it wrong. The right answer was 7.4 O.O
Does anybody understand why? I don't. 
it's weird, all right. 7.4 is the median. Surely not an outlier.

7.4 is correct because notice how if you put this on a scatter plot, all of the numbers are nice and smoothed out, however, 5 with 7.4 is really far out making the answer D

Well because if you notice that 0.9 is close to 1, and 2.1 is close to 2, 3.2 is close to 3, 3.9 is close to 4, but 7.4 is not close to 5, and 5.8 is close to 6, 7.2 is close to 7, 8 is close to 8, and 9.1 is close to 9. Do you see the pattern? 7.4 is the outlier.