Summary Statistics (Analysis)
Summary
Calculates summary statistics for field(s) in a table.
Usage

The Output Table will consist of fields containing the result of the statistical operation.

The following statistical operations are available with this tool: Sum, Mean, Maximum, Minimum, Range, Standard Deviation, Count, First, and Last. The Median operation is not available.

A field will be created for each statistic type using the following naming convention: SUM_FIELD, MAX_FIELD, MIN_FIELD, RANGE_FIELD, STD_FIELD, FIRST_FIELD, LAST_FIELD, COUNT_FIELD. The field name is truncated to 10 characters when the Output Table is a dBASE table.

If a Case field is specified, statistics will be calculated separately for each unique attribute value. The Output Table will contain only one record if no Case field is specified. If one is specified, there will be one record for each Case field value.

Null values are excluded from all statistical calculations. For example, the AVERAGE of 10, 5 and NULL is 7.5 ((10+5)/2). The COUNT tool returns the number of values included in the statistical calculation, which in this case is 2.

The Statistics Field(s) parameter Add Field button is used only in ModelBuilder. In ModelBuilder, where the preceding tool has not been run, or its derived data does not exist, the Statistics Field(s) parameter may not be populated with field names. The Add Field button allows you to add expected field(s) so you can complete the Summary Statistics dialog and continue to build your model.

When using layers, only the currently selected features are used to calculate statistics.
Syntax
Parameter  Explanation  Data Type 
in_table 
The input table containing the field(s) that will be used to calculate statistics. The input can be an INFO table, a dBASE table, an OLE DB table, a VPF table, or a feature class.  Table View; Raster Layer 
out_table 
The output dBASE or geodatabase table that will store the calculated statistics.  Table 
statistics_fields [[field, statistics_type],...] 
The numeric field containing attribute values used to calculate the specified statistic. Multiple statistic and field combinations may be specified. Null values are excluded from all statistical calculations. The Add Field button, which is used only in ModelBuilder, allows you to add expected field(s) so you can complete the dialog box and continue to build your model. Available statistics types are:
 Value Table 
case_field [case_field,...] (Optional) 
The fields in the Input Table used to calculate statistics separately for each unique attribute value (or combination of attribute values when multiple fields are specified).  Field 
Code Sample
The following Python window script demonstrates how to use the Statistics tool in immediate mode.
import arcpy from arcpy import env env.workspace = "C:/data/Habitat_Analysis.gdb" arcpy.Statistics_analysis("futrds", "C:/output/output.gdb/stats", [["Shape_Length", "SUM"]], "NM")
The following standalone script summarizes the vegetation by area within 150 feet of major roads.
# Name: Statistics_Example2.py # Description: Summarize the vegetation by area within 150 feet of major roads # Import system modules import arcpy from arcpy import env # Set environment settings env.workspace = "C:/data" # Set local variables inRoads = "majorrds.shp" outBuffer = "C:/output/output.gdb/buffer_out" bufferDistance = "250 feet" inVegetation = "Habitat_Analysis.gdb/vegtype" outClip = "C:/output/output.gdb/clip_out" joinField = "HOLLAND95" joinTable = "c:/data/vegtable.dbf" joinedField = "HABITAT" outStatsTable = "C:/output/output.gdb/stats_out" statsFields = [["Shape_Area", "SUM"]] # Execute Buffer to get a buffer of major roads arcpy.Buffer_analysis(inRoads, outBuffer, bufferDistance, dissolve_option = "ALL") # Execute Clip using the buffer output to get a clipped feature class # of vegetation arcpy.Clip_analysis(inVegetation, outBuffer, outClip) # Execute JoinField to add the vegetation type arcpy.JoinField_management(outClip, joinField, joinTable, joinField, joinedField) # Execute Statistics to get the area of each vegetation type within # the clipped buffer. arcpy.Statistics_analysis(outClip, outStatsTable, statsFields, joinedField)