Answer:
38
Explanation:
An outlier is a data point on a graph or in a set of results that is much bigger or smaller than the next nearest data point. The numbers given are within 1-3 points away from the previous number, except for 38, which is 14 points away from 24. Organize the numbers in order from least to greatest to see this better.
13, 14, 16, 17, 18, 21, 24, 38