MPOLISH procedure

Performs a median polish of two-way data (D.B. Baird).


Options

MAXCYCLE = scalar
Maximum number of iterations; default 50

TOLERANCE = scalar
Tolerance for convergence; default 0.0001


Parameters

DATA = variates or pointers or matrices or tables
Two-way data to be polished

ROWS = factors
Row definitions for a DATA variate

COLUMNS = factors
Column definitions for a DATA variate

ROWEFFECTS = variate
Row effects removed from polished results

COLEFFECTS = variate
Column effects removed from polished results

POLISH = variates or pointers or matrices or tables
Polished result in same format as DATA

CENTRE = scalars
Estimate of overall centre point


Description

MPOLISH performs a median polish of two-way data, supplied by the DATA parameter. This can be a two-dimensional table, a matrix or a pointer of variates. Alternatively, it can be a single variate. The rows and columns are then defined by factors supplied by the ROWS and COLUMNS parameters, or by just the COLUMNS parameter with the data valueS assumed to be sorted into row order within each column.

   The MAXCYCLE option sets a limit on the number of iterations. The TOLERANCE option specifies the convergence criterion: convergence occurs when

ABS(1-SUM(ABS(OldPolish)) / SUM(ABS(NewPolish))) < TOLERANCE

   The polished data can be saved by the POLISH parameter, row effects by the ROWEFFECTS parameter, column effects by the COLEFFECTS parameter, and the overall centre point by the CENTRE parameter.

 

Options: MAXCYCLE, TOLERANCE.

Parameters: DATA, ROWS, COLUMNS, ROWEFFECTS, COLEFFECTS, POLISH, CENTRE.