Re: Gallup organization on polling methods]

[E. Jacquelin Dietz]

I think that Gallup knows all the residential phone exchanges in the country. (As the article explains, a "phone exchange is a six-digit number: the area code and the first three additional numbers of the phone number.") They randomly sample exchanges, with probability proportional to the number of residential phone numbers in that exchange (which they evidently have some way to estimate). Then I think they just add a 4-digit random number to each exchange to generate a phone number. I don't think they know (or care) which numbers are listed or unlisted.

Jackie Dietz
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E. Jacquelin Dietz (919) 515-1929 (phone)
Department of Statistics, Box 8203 (919) 515-1169 (FAX)
North Carolina State University
Raleigh, NC 27695-8203 USA [EMAIL PROTECTED]

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