4. Principal Components in Item Residuals

Observe that the items are clearly classified into the two ends of a contrast factor. Table 23.3 shows them to be stratified into "Against Drugs" and "For Drugs" items.

TABLE 23.2 Recreational Drug Survey                 drugs.out Apr 12 15:18 1999
INPUT: 39 PERSONS, 20 ITEMS  ANALYZED: 39 PERSONS, 20 ITEMS, 5 CATS        v2.91
--------------------------------------------------------------------------------

       PRINCIPAL COMPONENTS (STANDARDIZED RESIDUAL) FACTOR PLOT
       Factor 1 explains 6.21 of 20 variance units
      -2              -1               0               1               2
      ++---------------+---------------+---------------+---------------++
      |                                |     A                          |
      |                                |                                |
   .8 +                                |                                +
      |                                |                                |
      |                                |                                |
      |                                |          B                     |
      |                                |                                |
   .7 +                                |                                +
      |                                |                                |
      |                                |   C                            |
   .6 +                                |                                +
      |                                |         D                      |
      |                                |      F   E                     |
F  .5 +                                |                                +
A     |                                |                              G |
C     |                                |                                |
T  .4 +                                |                                +
O     |                                |H                               |
R  .3 +                             I  |                                +
      |                                |                                |
1  .2 +                                |                J               +
      |                                |                                |
L  .1 +                                |                                +
O     |                                |                                |
A  .0 +--------------------------------|--------------------------------+
D     |                                |                                |
I -.1 +                                |                                +
N     |                                |                                |
G -.2 +                                |                                +
      |                                |                                |
  -.3 +                                |                                +
      |               j                |                                |
  -.4 +                                |                                +
      |                                |   i                            |
      |                                |                                |
  -.5 +                    g       h   |                                +
      |                               f|                                |
      |                                |                                |
  -.6 +                ed              |                                +
      |                  c             |                                |
      |                           b    |                                |
  -.7 +                                |                                +
      |                 a              |                                |
      ++---------------+---------------+---------------+---------------++
      -2              -1               0               1               2
                                 ITEM MEASURE

TABLE 23.3 Recreational Drug Survey                 drugs.out Apr 12 15:18 1999
INPUT: 39 PERSONS, 20 ITEMS  ANALYZED: 39 PERSONS, 20 ITEMS, 5 CATS        v2.91
--------------------------------------------------------------------------------

 FACTOR 1 FROM PRINCIPAL COMPONENT ANALYSIS OF
  STANDARDIZED RESIDUAL CORRELATIONS FOR ITEMS (SORTED BY LOADING)
   FACTOR 1 EXPLAINS 6.21 OF 20 VARIANCE UNITS
+---------------------------------------------------------+
|      |       |       INFIT OUTFIT| ENTRY                |
|FACTOR|LOADING|MEASURE  MNSQ MNSQ |NUMBER  ITEM          |
|------+-------+-------------------+----------------------|
|  1   |   .83 |     .35  .90  .87 |A   20 A:dope         |
|  1   |   .73 |     .67 1.61 1.75 |B    5 A:not use      |
|  1   |   .63 |     .24 1.05 1.04 |C    4 A:unnatural    |
|  1   |   .58 |     .63  .61  .60 |D   14 A:care-givers  |
|  1   |   .54 |     .69  .93  .95 |E    6 A:psycho       |
|  1   |   .54 |     .43  .82  .84 |F   17 A:stupid       |
|  1   |   .48 |    1.94  .63  .64 |G   19 A:side-effects |
|  1   |   .33 |     .07  .95  .93 |H    2 A:dangerous    |
|  1   |   .31 |    -.19 1.37 1.40 |I   11 A:no-aspirin   |
|  1   |   .18 |    1.08  .59  .61 |J    3 A:regret       |
|      |-------+-------------------+----------------------|
|  1   |  -.71 |    -.93 1.24 1.26 |a   12 F:relationship |
|  1   |  -.66 |    -.31 1.06 1.07 |b    7 F:trip         |
|  1   |  -.64 |    -.90 1.60 1.47 |c   10 F:high         |
|  1   |  -.62 |    -.93  .81  .79 |d    8 F:stoned       |
|  1   |  -.59 |   -1.00 1.02 1.19 |e   13 F:drug-scene   |
|  1   |  -.55 |    -.04  .96  .95 |f   15 F:experience   |
|  1   |  -.50 |    -.74  .66  .79 |g   16 F:fun          |
|  1   |  -.50 |    -.25 1.27 1.22 |h    1 F:legal        |
|  1   |  -.44 |     .26  .71  .71 |i   18 F:less-alcohol |
|  1   |  -.35 |   -1.08  .97  .94 |j    9 F:calm         |
+---------------------------------------------------------+

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