Should I do the neilson TV survey, has anyone done it?!

I received a card in the mail saying they were the Neilson TV ratings ppl and that they would be calling me, they did, they asked a few questions about the ages of ppl in my house, our race etc!. and then they said they'd be mailing me a log to keep track of what we watch during a 1 week period and a prepaid envelope to mail them back in!.!.!.!. Has anyone done it that can suggest whether or not to do it!? also, they're sending $30 with it as a thank you for doing it!. do you think it's ok to deposit the check!? i'm just worried it's a scam to get my bank account info and would like to hear from ppl who have done it before!.
Thanks for your help!!! :o)Www@Enter-QA@Com

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