SPSS Populate Scratch Variable with Standard Deviation

Question

I am just learning SPSS, I have a background in PL/SQL and T-SQL

I have a dataset and need to make three groups based on deviation from the mean for a specific variable

Greater than 1 Standard Deviation Above the Mean

Greater than 1 Standard Deviation Below the Mean

All Others

I wanted to use a scratch variable but have no idea how to find the standard deviation of an existing variable and populate it into a scratch variable to use for my grouping conditions.

Any help appreciated

Answer 1

The aggregate command can calculate the SD of a variable and add it to the dataset, like this:

aggregate/outfile=* mode=addvariables/break= 
        /SDyourvar=sd(yourvar) /MEANyourvar=mean(yourvar).

Now you can use the variables to create groups like this for example:

do if yourvar < (MEANyourvar - SDyourvar).
   compute group=-1.
else if yourvar > (MEANyourvar + SDyourvar).
   compute group=1.
else.
   compute group=0.
end if.

Or for a shorter version:

compute group=(yourvar > (MEANyourvar+SDyourvar)) - (yourvar < (MEANyourvar-SDyourvar)).