Factor Analysis and Principal Components Analysis 239
where
=
Y
yy
yy
yy
N
tNt
TNT
11 1
1
1
is the matrix of the data, in which every row corresponds to an observa-
tion of all N variables, and each column corresponds to all T observa-
tions of each variable; and where
=
F
ff
ff
ff
1
1
1
q
tqt
TqT
11 1
1
1
is the matrix of factors where we add a column of ones to include the
constant terms a (note that the terms of this matrix are not observable)
=
C
aa
bb
bb
N
N
qNq
1
11 1
1
is the matrix of factor loadings plus the terms a in the first row.
=
εε
εε
εε
E
N
tNt
TNT
11 1
1
1
is the matrix of error terms, which are not observable.