000915 : The General G statistic was designed to work with positive attribute values.

Description

This mathematics associated with this tool can only evaluate spatial clustering of high/low positive values. It cannot be used to assess clustering for fields containing negative values.

Solution

Use a different input field for this analysis. Select a field that only contains values greater than or equal to 0. Alternatively, adjust the values in the field (add a constant) so that all values are larger than 0.