CORRESP <data>,L
performs a correspondence analysis on a table (of frequencies) saved
as a Survo data set. The rows are the active observations (chosen by
IND, CASES, and SELECT specifications) and the columns are the variables
activated by `A's.
The extent of results is determined by activating more variables by
other mask characters. For example, the row coordinates are saved
in variables activated by `C's. The corresponding column coordinates
are saved in a matrix file CR_COORD.M .
In summary, the results are selected as follows:
In columnwise results:
Mask Task Matrix file for
C Row coordinates CR_COORD.M Column coordinates
S Supplementary columns CR_SUPPC.M Column coordinates
u U from SVD CR_V.M V from SVD
CR_EIGEN.M D^2 from SVD
a Absolute contributions CR_CONTR.M for columnwise contributions
s Squared correlations CR_CORR2.M for columnwise squared corr.s
r Residuals of the original table
m Mass (one variable) CR_MDIST.M 1st column
d Chi^2 distance CR_MDIST.M 2nd column
Above, SVD stands for the singular value decomposition A=UDV' of matrix
A=Em*F*En
where F is the original m x n matrix, Em is a diagonal matrix with the
inverse square roots of the row sums as diagonal elements and En is
similarly related to the column sums.
Supplementary cases (rows) are indicated by a specification
SUPPL_CASES=<variable>,<l.limit>,<u.limit>
/CRPLOT <data>,<C1>,<C2>,<C_coord>,<S_coord> / K.Vehkalahti
creates a correspondence plot of dimensions <C1> and <C2> so that the
information from <data> and two matrices are presented in the same
coordinate system.
Reference:
Lebart, Morineau, Warwick: Multivariate Descriptive Statistical
Analysis, (Wiley 1984)
See also MCORRESP? (Multiple Correspondence Analysis)
An example on the next page:
Example:
Before plotting, activate the CORRESP operation below!
HEADER=Fisher's_example:_Hair_and_eye_colors_of_children_in_Caithness,_Scotland
GPLOT COLORS,C1,C2 / POINT=[RED],Color OUTFILE=A
SCALE=-1,0,1.5 MODE=VGA XDIV=179,380,80 YDIV=59,380,40
...................................................................................................
GPLOT CR_COORD.M,C1,C2 / POINT=[BLUE],CASE HEADER= INFILE=A
SCALE=-1,0,1.5 MODE=VGA XDIV=179,380,80 YDIV=59,380,40
...................................................................................................
DATA COLORS,A,B,N,M
------ AAA AAA AAA AAA CC.CC CC.CC rrrr rrrr rrrr rrrr aa.a aa.a ss.ss ss.ss mm.mm dd.dd
Color BLUE LIGHT MEDIUM DARK C1 C2 BL LI ME DA ABS1 ABS2 S1 S2 Mass Dist
Fair 326 688 343 98
Red 38 116 84 48
Medium 241 584 909 403
Dark 110 188 412 681
Black 3 4 26 85
CORRESP COLORS,CUR+1
M = More information on multivariate analysis
Help System (web edition)