Date:         Fri, 22 Oct 2010 21:12:24 +0200
Reply-To:     John F Hall <johnfhall@orange.fr>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         John F Hall <johnfhall@orange.fr>
Subject:      Re: Help with Square Matrix
Content-Type: multipart/alternative;

Cy

Art has already supplied a solution, but you don't say how many students there are in total, but one thing you could try (if there are not too many) would be to feed the data in as two string variables columna and columnb and then do:

crosstabs columna by columnb .

Thiswould at least show you the combinations.

John Hall
johnfhall@orange.fr 
http://surveyresearch.weebly.com 

  ----- Original Message ----- 
  From: Chao Yawo 
  To: SPSSX-L@LISTSERV.UGA.EDU 
  Sent: Friday, October 22, 2010 7:29 AM
  Subject: Help with Square Matrix


Hi,

I have a dataset with the following structure.


ColumnA            ColumnB         ColumnC         
ClassA            OtherStud        WorkWith        

AA                     DD                1         
AA                     EE                0         
AA                     BB                1         
BB                     FF                1         
BB                     GG                1          
BB                     KK                0         
CC                     AA                1         
CC                     BB                1         


ColumnA refers to students in ClassroomA, and Column B refers to "Other
Students" in the school who could act as work and/or playmates.  Note, ColumnB could also include some of the same students in ColumnA(ClassA) who work with each other (For example, Students: AA and BB).

If a Student in Classroom A works with a student in ClassroomB, ColumnC
takes the value of 1, and 0(zero) if otherwise

So, looking at ColumnA, we find that there are three students:  AA, BB and
CC. Student_AA for instance interacts with three students <DD, EE, BB> but only
works with DD and BB.  Similarly, Student_CC interacts with two students
<AA, and BB> and works and plays with each of them.

Now, I am interested in constructing a matrix indicating which
students in ClassroomA work with each other. This means
that student_AA for instance works with student_BB, who is in his/her
classroom, hence the cell in their matrix will have a "1".  Again, Student_CC in ClassroomA works with 2 other members of
his/her own class<ie, AA and BB>.  So CC would have two "1s" in the matrix.

The resulting matrix for the "Works With" relation (ColumnC) among the 3
students in ClassroomA would look like this.

        AA    BB      CC
AA      0     1        0
BB      0     0        0
CC      1     1        0

This matrix is the output I am interested in, and need to produce for the relationship specified in Column C.I would certainly appreciate some ideas to help me produce this.


Thanks in advance for your assistance.

Sincerely, Cy


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