Calculates partial correlations for a list of variates (S. Langton).
Options
PRINT = string token |
Output required (correlations); default corr |
|---|---|
CORRELATIONS = symmetric matrix |
Saves the partial correlations |
WEIGHTS = variate |
Supplies weights for the units; default * i.e. all 1 |
Parameters
DATA = variates |
Set of variates whose partial correlations are to be calculated |
|---|
Description
PARTIALCORRELATIONS calculates a symmetric matrix of partial correlations from a set of variates. The matrix contains the correlation between each pair of variates after adjusting for all the other variates in the set. The variates are listed using the DATA parameter, and the matrix can be saved using the CORRELATIONS option. A variate of weights can be supplied using the WEIGHTS option. The PRINT option controls the printing of the partial correlations. The default setting correlations ensures that they are printed, but you can set PRINT=* to suppress printing.
Options: PRINT, CORRELATIONS, WEIGHTS.
Parameter: DATA.
Method
The partial correlations are calculated from the correlations C by the calculation
-CORRMAT( INVERSE(C) )
Action with RESTRICT
Any units that are restricted within the DATA variates (or which have missing values) are excluded from the analysis.
See also
Directive: CORRELATE.
Procedures: DCORRELATION, FCORRELATION, PRCORRELATION, SCORRELATION.
Example
CAPTION 'PARTIALCORRELATIONS example',\
!t('Leaf burning time of tobacco (Steel & Torrie,',\
'Principals and Procedures of Statistics, p.282 & 285,',\
'McGraw Hill, New York).'); STYLE=meta,plain
VARIATE Nitrogen,Chlorine,Potassium,LogBurn
READ Nitrogen,Chlorine,Potassium,LogBurn
3.05 1.45 5.67 0.34 4.22 1.35 4.86 0.11 3.34 0.26 4.19 0.38
3.77 0.23 4.42 0.68 3.52 1.10 3.17 0.18 3.54 0.76 2.76 0.00
3.74 1.59 3.81 0.08 3.78 0.39 3.23 0.11 2.92 0.39 5.44 1.53
3.10 0.64 6.16 0.77 2.86 0.82 5.48 1.17 2.78 0.64 4.62 1.01
2.22 0.85 4.49 0.89 2.67 0.90 5.59 1.40 3.12 0.92 5.86 1.05
3.03 0.97 6.60 1.15 2.45 0.18 4.51 1.49 4.12 0.62 5.31 0.51
4.61 0.51 5.16 0.18 3.94 0.45 4.45 0.34 4.12 1.79 6.17 0.36
2.93 0.25 3.38 0.89 2.66 0.31 3.51 0.91 3.17 0.20 3.08 0.92
2.79 0.24 3.98 1.35 2.61 0.20 3.64 1.33 3.74 2.27 6.50 0.23
3.13 1.48 4.28 0.26 3.49 0.25 4.71 0.73 2.94 2.22 4.58 0.23 :
PARTIALCORRELATIONS Nitrogen,Chlorine,LogBurn