STATS Process

To access this process:

Sample Analysis ribbon >> Statistics >> Statistics Processes >> Summary Statistics.
View the Find Command screen, select STATS and click Run.
Enter "STATS" into the Command Line and press <ENTER>.

See this process in the Command Table.

Process Overview

Calculate general summary parametric statistics on numeric fields in a file.

Individual fields for statistics may be selected using either the *F1, *F2, etc fields or may be specified in the &FIELDLST file. If no fields are selected then statistics will be calculated for all fields.

Ten optional keyfields are provided. If no keyfields are specified then a single set of statistics will be calculated for all data. If keyfields are specified and parameter KEYSORT=1 or the input file is already sorted by keyfield then statistics will be calculated for each unique combination of key values. If keyfields are specified and parameter KEYSORT=0 and the input file is not sorted by keyfield then data will be read from the input file until the value of one of the keyfields changes and the statistics will then be calculated for that data subset.

Note: A limit of 256 fields is imposed. If more than 256 fields exist in &IN, the process will not complete.

An optional weighting field (*WEIGHT) is available to weight the sample data. For example in a desurveyed drillhole file the LENGTH field could be used as the weighting field to give length weighted grades.

Note: When calculating MAD and percentile statistics, WEIGHT is ignored.

The variance and other moments are calculated using the large sample method (for the variance a divisor of N is used, where N is the number of samples).

The following statistics are calculated for each numeric variable :-

total number of records in the file that meet retrieval criteria, if specified
number of samples (excluding absent data).
number of absent data values.
minimum, maximum, range and mid-range.
total and mean.
variance, standard deviation and standard error.
skewness and kurtosis.
geometric mean.
Sum, mean and variance of natural logs.
log estimate of mean.
coefficient of variation in percent.
number of records equal to zero.
number of negative value.

These results are displayed in the Command window and can also be saved to an optional &OUT file..

If the PCNTILES parameter is set to 1 then the 5, 10, 20, 25, 30, 40, 50, 60, 75, 80, 90 and 95 percentiles and the Median Absolute Deviation are also calculated. Processing will take longer. If this option is selected it is helpful to specify only the fields for which you wish to calculate the statistics. The Weight field is not used when calculating percentiles.

By default, statistics are calculated for all numeric variables. For example; in a typical drillhole data file containing sample co-ordinates, statistics will be calculated for both the values and the co-ordinates. The first bin in the histogram plot contains all values up to MINIMUM. The last bin contains all values above the top value. The log statistics are based on all sample values greater than, but not equal to, the system trace value.

Values of skewness and kurtosis calculated are interpreted as:

SKEWNESS	= 0. No distortion (Gaussian).
	> 0. Positive skew (to the right).
	< 0. Negative skew (to the left).
KURTOSIS	= 0. Mesokurtic (Gaussian).
	> 0. Leptokurtic (peaked).
	< 0. Platikurtic (flat).

Missing Values

When the STATS process is run with retrieval criteria, data that is excluded by those criteria will not be reported. This is a change from previous versions which classified excluded data as "Missing Values".

The following fields are also output:

NSAMPLES – The number of samples in the chosen numeric (F1 etc) fields that are non-absent and used to calculate statistics.
NMISVALS – The number of missing records in the chosen numeric (F1 etc) fields. Samples are classified as missing if they have an absent value.
NUMTRACE – The number of samples in the chosen numeric (F1 etc) fields that are equal to the TRACE value
EQUAL0 – The number of records in the chosen numeric (F1 etc) fields that contain values that = 0.
NEGATIVE – The number of records in the chosen numeric (F1 etc) fields that contain negative values.

Input Files

Name	Description	I/O Status	Required	Type
IN	Input file.	Input	Yes	Table
FIELDLST	File to supply selected fields.	Input	No	Undefined

Output Files

Name

I/O Status

Required

Type

Description

OUT

Output

Table

Output file. This will contain the fields:

FIELD: field for which statistics have been calculated
NRECORDS: total number of records in the input data (including those excluded by retrieval criteria)
NSAMPLES: number of records (samples) used to calculate the statistics
NMISVALS: number of missing values - either absent or excluded by retrieval criteria
NUMTRACE: number of samples equal to TRACE
MINIMUM: minimum sample value
MAXIMUM: maximum sample value
RANGE: range of the sample values
TOTAL: sum of the sample values
MEAN: mean of sample values
VARIANCE: variance of the sample values (Absent if fewer than two sample values)
STANDDEV: standard deviation of the input sample values
STANDERR: standard error of the input sample values
SKEWNESS: skewness of the sample values
KURTOSIS: kurtosis of the sample values
GEOMEAN: geometric mean of the input sample values
SUMLOG: sum of the sample log values
MEANLOG: mean of the sample log values
LOGVAR: variance of the sample log values (If more than one sample value)
LOGESTM: log estimate of the mean
COVARTN%: coefficient of variation in percent
MIDRANGE: value mid-way between the minimum and maximum values
EQUAL0: number of samples with a value of zero
NEGATIVE: number of negative samples
WGTFIELD: weight field used
DATAFILE: name of the input data file

If keyfields have been specified then they will also be included. There will be one record for each numeric field for every combination of keyfields.

Fields

Name	Description	Source	Required	Type	Default
F1-20	Fields for statistics. If no fields are specified then all fields will be used.	IN	No	Numeric	Undefined
FIELDNAM	Field in FIELDLST to identify selected fields.	FIELDLST	No	Character	Undefined
KEY1-10	Key fields 1 for statistics.	IN	No	Any	Undefined
WEIGHT	Weighting field.	IN	No	Numeric	Undefined

Parameters

Name	Description	Required	Default	Range	Values
KEYSORT	Set to 1 to automatically sort the data by key field. Only relevant if any key fields have been defined. =0 : Do not automatically sort by key fields. Use the record order of the input file to determine changes in key field values. =1 : Automatically sort the input data by key fields.	No	No	Numeric	Undefined
KEYTOL	The tolerance used to test whether numeric key fields are equal. All key values are rounded to an integer multiple of this value. If set to zero then rounding will not be used.	No	0.00001	0,+	Undefined
PCNTILES	Set to 1 to calculate percentiles. When calculating percentiles the process will take longer to run. If this option is selected it is useful to specify only the fields for which you wish to calculate the statistics. If this option is selected the Median Absolute Deviation (MAD) value is also calculated. =0 : Do not calculate percentiles. Do not calculate the Median Absolute Deviation. =1 : Calculate the 5, 10, 20, 25, 30, 40, 50, 60, 75, 80, 90 and 95 percentiles and the Median Absolute Deviation.	No	0	0,1	0,1
SORTOUT	Set to 1 to sort the output file by FIELD when key fields are being used. Sorting by FIELD makes it easier to compare values of variables across key fields when viewing the output file in the table editor. =0 : Do not sort the output file. =1 : Sort the output file by FIELD.	No	1	0,1	0,1
PRINT	Print flag. Default (2). 0: minimum output. 1: minimum output plus key field progress list. 2: full output including stats for each key field group.	No	2	0-2	0,1,2

Example

Copy

!STATS    &IN(ASSAYS), &OUT(DHSTATS), *F1(AU), *F2(AG), 
*F3(CU),*WEIGHT(LENGTH)

Error and Warning Messages

Message	Description	Solution
>>> ERR 121 <<< ( fileno) IN STATS	File read error. Fatal; the process is exited.	Check the values of the fields in the specified &IN file.
>>> ERR 122 <<< ( fileno) IN STATS	No numeric fields in file, or fields specified were not numeric. Fatal; the process is exited.	In the &IN file, check that the specified *Fn fields are numeric; check that the file contains numeric fields.