Multivariate Data Screening Charts

Exploratory Outlier Analysis Chart

The exploratory outlier analysis chart allows:

  • Exploratory visualization of outlier analysis
  • Classify zones that include groups of objects with different range of Mahalanobis distance below the outlier zone
  • Defining groups of objects based on defined zones (i.e., mapping the color of different zones to the source worksheet object markers)

The chart can be generated based on either Mahalanobis distance or jackknifed Mahalanobis distance.

Example Graph

The outlier chart on this page was plotted from a wireline log data set with 2055 object. The outlier threshold was defined at chi-squared=97.5%; the data below the outlier threshold were classified into three zones based on the range of Mahalanobis distance from the multivariate mean.

An Exploratory Outlier Chart and the Corresponding Range of Mahalanobis Distance Values in the Defined Zones

Exploratory Outlier Analysis Chart