Dataplot Vol 2 Vol 1

# DEX CORE

Name:
DEX CORE (LET)
Type:
Let Subcommand
Purpose:
Determine the core vectors spanning the (n-1) space (or a large part of it) for effect estimation in the analysis of 2-level full and fractional factorial designs.
Description:
The "dex10stepanalysis.dp" macro can be used to analyze 2-level full or fractional factorial designs. A key step in the analysis of these designs is the estimation of the effects and the determination of the confounding structure. The "dex10stepanalysis.dp" macro calls the "compute_effect_estimates_and_confounding.dp" macro to perform the effect estimation. The DEX CORE command is a utility command used in the "compute_effect_estimates_and_confounding.dp" macro and is not typically used outside of this context.

Previous versions of the 10-step analysis macros contained a "core.dp" macro. The DEX CORE command emulates the computations of this macro.

The input to this command is the factor variables of the design matrix. The response variable is not needed. The output is a matrix containing five core factors.

Syntax:
LET <m> = DEX CORE <x1> ... <xk>
where <x1> ... <xk> is a list of 1 to k variable names;
<m> is a matrix where the core factors will be saved;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
LET CORE = DEX CORE X1 X2 X3
LET CORE = DEX CORE X1 X2 X3 X4 X5

LET STALL = STRING COMBINE X1 TO X8 LET CORE = DEX CORE ^STALL

Default:
None
Synonyms:
None
Related Commands:
 DEX CONFOUND = Determine the confounding structure of a 2-level full or fractional factorial design. CODE DEX = Convert data to -1, 0, +1 coding. CODE DEX 2-LEVEL = Generate a coded variable for a factor variable used in analyzing a 2-level full or fractional factorial design. DEX CHECK CLASSIC = Check if factor variables are in classic ("-1", "+1") form. DEX CHECK CENTER POINTS = Given a list of factor variables, create a tag variable that will identify center points.
Applications:
Analysis of 2-level full and fractional factorial designs
Implementation Date:
2018/02
Program:
```
skip 25
read scott_8_16.dat y x1 to x8
let string stall = string combine x1 to x^k
let corefa = dex core ^stall
set write decimals 3
print corefa
```
The following output is returned
```
MATRIX CORE    --           15 ROWS
--            5 COLUMNS

VARIABLES--CORE1          CORE2          CORE3          CORE4          CORE5

1.000       -999.000       -999.000       -999.000       -999.000
2.000       -999.000       -999.000       -999.000       -999.000
3.000       -999.000       -999.000       -999.000       -999.000
4.000       -999.000       -999.000       -999.000       -999.000
5.000       -999.000       -999.000       -999.000       -999.000
6.000       -999.000       -999.000       -999.000       -999.000
7.000       -999.000       -999.000       -999.000       -999.000
8.000       -999.000       -999.000       -999.000       -999.000
1.000          2.000       -999.000       -999.000       -999.000
1.000          3.000       -999.000       -999.000       -999.000
1.000          4.000       -999.000       -999.000       -999.000
1.000          5.000       -999.000       -999.000       -999.000
1.000          6.000       -999.000       -999.000       -999.000
1.000          7.000       -999.000       -999.000       -999.000
1.000          8.000       -999.000       -999.000       -999.000
```

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

Date created: 11/08/2018
Last updated: 11/08/2018