At the beginning
of your session: Do Transform> Random number seed> Make sure Random Seed is selected, and click OK.
This does the equivalent of closing your eyes and putting your finger
on the random number table page, to start with.
(Without your clicking OK, it starts with seed 2,000,000. ) Now you
(and others) will get a different sequence of random numbers/samples
even though you open SPSS and do exactly the same thing. You only
need to do it once, to start each SPSS session.
What if you might want to repeat a process exactly, getting the same " random" sample again? Do Transform> Random number seed> Choose Set Seed: You can put in any number from
1 to 2,000,000,000. (Then, if you
want to repeat your session exactly, you could do Transform>Random
number seed>Choose Set Seed, put in the same number again, do OK, and it would then reset to the same starting point.)
How to ensure you're not using a seed you -- or someone else in the class -- has used? How about this? The hour, minutes, seconds, month, and day, right now: hhmmssmmdd, or h,hmm,ssm,mdd It fits, and is unlikely to be ever duplicated. Do OK. Don't reset again for this session, it'll just keep churning out its random numbers as if reading across sequential lines in the random number table. If you think you'll want to repeat the process, write down your seed.
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