Which data set has an outlier? 6, 13, 13, 15, 15, 18, 18, 22 4, 4, 4, 8, 9, 9, 11, 18 2, 3, 5, 7, 8, 8, 9, 10, 12, 17 3, 6, 7, 7, 8, 8, 9, 9, 9, 10