Dataplot Vol 2 Vol 1

# H CONSISTENCY STATISTIC

Name:
H CONSISTENCY STATISTIC (LET)
Type:
Let Subcommand
Purpose:
Compute the h-consistency statistic of a variable as defined by the ASTM E691 standard.
Description:
The h-consistency statistic is defined in the ASTM E691 standard as

$$h = d/s_{\tilde{x}}$$ (between laboratory consistency statistic)

with

d = cell deviation (cell average - average of cell averages)
$$s_{\tilde{x}}$$ = standard deviations of cell averages

Essentially, h is a standardized deviation from the grand averages.

Syntax 1:
LET <h> = H CONSISTENCY STATISTIC <y> <labid>
<SUBSET/EXCEPT/FOR qualification>
where <y> is a response variable;
<labid> is a lab-id variable;
<h> is a variable where the h-consistency statistic values are saved;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

This syntax is used to compute the h-consistency statistic for a single material. The number of h-values is equal to the number of laboratories.

Syntax 2:
LET <h> <labtag> <mattag>= H CONSISTENCY STATISTIC <y> <labid> <matid>
<SUBSET/EXCEPT/FOR qualification>
where <y> is a response variable;
<labid> is a lab-id variable;
<matid> is a material-id variable;
<h> is a variable where the h-consistency statistic values are saved;
<labtag> is a variable where the corresponding lab-id values are saved;
<mattag> is a variable where the corresponding material-id values are saved;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

This syntax is used to compute the h-consistency statistic for multiple materials. The number of h-values is equal to the number of materials times the number of laboratories.

Examples:
LET A = H CONSISTENCY STATISTIC Y LAB
LET HVAL = H CONSISTENCY STATISTIC Y LAB MAT
LET HVAL = H CONSISTENCY STATISTIC Y LAB MAT SUBSET MAT > 2
Default:
None
Synonyms:
None
Related Commands:
 E691 INTERLAB = Perform an E691 interlab analysis. H CONSISTENCY PLOT = Generate an h consistency plot. K CONSISTENCY STATISTIC = Compute the k-consistency statistic.
Reference:
"Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method", ASTM International, 100 Barr Harbor Drive, PO BOX C700, West Conshohoceken, PA 19428-2959, USA.
Applications:
Interlaboratory Analysis
Implementation Date:
2005/4
Program:
SKIP 25
.
LET HVAL LABTAG MATTAG = H CONSISTENCY STATISTIC Y LABID MATID
.
SET WRITE DECIMALS 4
PRINT HVAL LABTAG MATTAG

The following output is generated
---------------------------------------------
HVAL         LABTAG         MATTAG
---------------------------------------------
-0.3877         1.0000         1.0000
-0.1292         2.0000         1.0000
-0.1127         3.0000         1.0000
-0.1017         4.0000         1.0000
-0.0907         5.0000         1.0000
0.8277         6.0000         1.0000
-1.7516         7.0000         1.0000
1.7461         8.0000         1.0000
-1.3592         1.0000         2.0000
-0.4450         2.0000         2.0000
0.2231         3.0000         2.0000
1.8487         4.0000         2.0000
-0.9869         5.0000         2.0000
0.2132         6.0000         2.0000
-0.1591         7.0000         2.0000
0.6653         8.0000         2.0000
-0.7328         1.0000         3.0000
0.0993         2.0000         3.0000
-0.2082         3.0000         3.0000
2.1413         4.0000         3.0000
-0.7064         5.0000         3.0000
0.5549         6.0000         3.0000
-0.9976         7.0000         3.0000
-0.1504         8.0000         3.0000
-0.4112         1.0000         4.0000
0.1501         2.0000         4.0000
-1.0124         3.0000         4.0000
0.9619         4.0000         4.0000
-0.6424         5.0000         4.0000
0.9735         6.0000         4.0000
-1.3322         7.0000         4.0000
1.3126         8.0000         4.0000
-0.4600         1.0000         5.0000
1.6429         2.0000         5.0000
-0.6766         3.0000         5.0000
0.4931         4.0000         5.0000
-0.3449         5.0000         5.0000
0.1725         6.0000         5.0000
-1.6172         7.0000         5.0000
0.7901         8.0000         5.0000

NIST is an agency of the U.S. Commerce Department.

Date created: 04/19/2005
Last updated: 06/30/2015