Focus on Relationships between variables - an example
  165.  PREMARITAL SEX ATTITUDES-  FEMALE         VALUES IN THE TABLE 
    Expected  Disapproved  Disallowed             ARE PERCENTS
      ________Y_________________         63. 
     |__1-2___|__3-4___|___5-6_|   COMMUNITY SIZE    N                  
 X   |                         |
    1|   63        5        32 |      < 50           19
    2|   56       22        22 |     50-99           18
    3|   44       35        21 |    100-199          34
    4|   45       25        30 |    200-399          20
    5|___48___    26        26 |    400-999          23
    6    11   |   33        56 |  1,000-4,999         9
    7     0   |___40___     60 |  5,000-49,999        5
    8     0        0   |___100_|      > 50,000        2

 Totals  58       33        39                      130
   r = .257  p < .01 (significant -- using Fisher-b)

  This example of a table, from a student project, shows us a relationship between 
  Community Size and Premarital Sexual Attitudes for females.  The table was made 
  with MAPTAB (World Cultures 7(2):2-25, see DW if you want a copy of the Tutorial), 
  but can be done just as easily in SPSS using files 3 and 7).  I want to call your
  attention to the asymmetric relationship between the two variables:

     If --------X----- (more X)  then ---------Y---------------- (more Y)
  1. As Community Size increases ---> Approval of Premarital Sex (1-2) drops off and
                                      drops off quickly above sizes of 1,000
                                      to more widespread disapproval (3-4; 5-6).

  This is a conditional relationship: the converse relationship is not so strong.

     If --------X----- (less X)  then ---------Y---------------- (less Y)
  2. As Community Size decreases ---> disapproval may drop (but not always), 
                                      but below 1,000 tendency is very small.  

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  Quick Review of Forms of relationship: (predicate logic)

  Root Form:                                Opposite (Negative)

  1. If X then Y (or more Y)                2. If X then not Y (less Y)

  Converse (doesnt follow from the root)    Opposite of Converse

  3. If Y then X (or more X)                4. If Y then not X (less X)
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  Each of these distinct statements has an equivalent contrapositive:

  Root Form Contrapositive:                 Contrapositive of Opposite 

  1. If NOT Y then NOT X (or LESS X)        2. If Y then not X (MORE X)

  Contrapositive of Converse                Contrapositive of Opposite of Converse

  3. If NOT X then NOT Y (or LESS Y)        4. If X then not Y (MORE Y)
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 (Note that I stated the converse in the example in contrapositive form, form  3.) 
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 Take home: JUST GETTING YOUR LOGIC STRAIGHT IS HALF THE BATTLE