We look through the data to see if any values are smaller than -4 or larger than 52. That is, we're looking for values that lie beyond the fences. And, we have one: 54. The 54 would be considered an outlier for this data set.

Consider the data set: { 12, 15, 27, 16, 14, 20, 21, 4, 19, 22 }.