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DEX CHECK CENTER POINTSName:
For 2-level full or fractional factorial design, the low level is typically coded as "-1" and the upper level is typically coded as "+1". Center points are typically coded as "0". In some cases, the data may be in the original units rather than the coded units. This command uses the following algorithm to determine whether a given row is a center point.
where <name1> <name2> ... <namek> is a list of 1 to k variable names; and where <tag> is a variable where the center point status is' saved. All of the variables on the right hand side should be of the same length. These should be the factor variables of the design matrix. Do not include the response variable.
If a given row of the design matrix is identified as a center point,
the corresponding row of
This TAG variable can be used to subset out the center point when
needed.
LET TAG = DEX CHECK CENTER POINT X1 X2 X3 X4 X5
should be coded as
LET IFLAG = DEX CHECK CENTER POINT ^STALL
LET NCENT = SIZE TAG SUBSET TAG = 0 If NCENT is equal to 0, then no center points are present.
let k = 8 skip 25 read scott_8_16.dat y x1 to x^k let stall = string combine x1 to x^k let tag = dex check center point ^stall set write decimals 0 print x1 to x^k tagThe following output is returned --------------------------------------------------------------------------------------------------------------------------------------- X1 X2 X3 X4 X5 X6 X7 X8 TAG --------------------------------------------------------------------------------------------------------------------------------------- -1 -1 -1 -1 -1 -1 -1 -1 1 1 -1 -1 -1 -1 1 1 1 1 -1 1 -1 -1 1 -1 1 1 1 1 1 -1 -1 1 1 -1 -1 1 -1 -1 1 -1 1 1 1 -1 1 1 -1 1 -1 1 -1 -1 1 1 -1 1 1 -1 -1 1 -1 1 1 1 1 1 -1 -1 -1 1 -1 1 -1 -1 -1 1 1 1 -1 1 1 1 -1 -1 1 1 -1 1 -1 1 -1 1 -1 1 -1 1 1 -1 1 1 1 -1 1 -1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 1 1 -1 1 1 -1 1 -1 -1 1 -1 1 1 1 1 -1 -1 -1 1 1 1 1 1 1 1 1 1 1
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Date created: 10/16/2018 |