Sort the data from smallest to largest
Calculate the mean and standard deviation
Find values more than 2 or 3 standard deviations from the mean
Calculate the interquartile range (IQR)
Compute Q1 and Q3
Find the lower fence: Q1 – 1.5 × IQR
Find the upper fence: Q3 + 1.5 × IQR
Identify any values below the lower fence or above the upper fence
Check for values that are far from the rest of the data
Compare the suspected value with the overall pattern of the dataset