In this video I explain how to use the interquartile range in order to identify possible outliers in a data set. This can be done using the interquartile range times 1.5 for moderate outliers, or times 3 for extreme outliers. This distance then creates a boundary below the 25th percentile and a boundary above the 75th percentile, creating a range for acceptable data points and excluding scores below and above those boundaries from analyses.