Last Update: 8/7/2015
For a dataset from repeated measurements, generating a Q-Q plot would help to visualize outliers.
A Q-Q plot is a graphic method for testing whether a dataset follows a given distribution, but it may also be used to determine outliers.
The expected values are not following the reference line, indicating the data was not normally distributed, the data points away from the reference lines are suspected outliers.
One should remove or mask the suspected outliers from the Q-Q plot, and when the expected values follow the reference line, all outliers are eliminated.
Keywords:outlier, Q-Q plot, probability plot, mask, detect outlier