Poll: How old are you?

VOLUNTARY RESPONSE POLLS

One professor of statistics, who is a co-author of a highly regarded AP statistics textbook, has tried to popularize the phrase that "voluntary response data are worthless" to go along with the phrase "correlation does not imply causation." Other statistics teachers are gradually picking up this phrase.

[quote=Paul Velleman]

-----Original Message----- From: Paul Velleman [SMTPfv2@cornell.edu] Sent: Wednesday, January 14, 1998 5:10 PM To: apstat-l@etc.bc.ca; Kim Robinson Cc: mmbalach@mtu.edu Subject: Re: qualtiative study

Sorry Kim, but it just aint so. Voluntary response data are worthless. One excellent example is the books by Shere Hite. She collected many responses from biased lists with voluntary response and drew conclusions that are roundly contradicted by all responsible studies. She claimed to be doing only qualitative work, but what she got was just plain garbage. Another famous example is the Literary Digest "poll". All you learn from voluntary response is what is said by those who choose to respond. Unless the respondents are a substantially large fraction of the population, they are very likely to be a biased -- possibly a very biased -- subset. Anecdotes tell you nothing at all about the state of the world. They can't be "used only as a description" because they describe nothing but themselves.[/quote]

http://mathforum.org/kb/thread.jspa?threadID=194473&tsta...

For more on the distinction between statistics and mathematics, see

http://statland.org/MAAFIXED.PDF

and

http://repositories.cdlib.org/cgi/viewcontent.cgi?article=10...

Good on you to say "most respondents" rather than "most users." This voluntary response poll will tell us nothing reliable about most users of HN, even if more than half of all users respond (which is not particularly likely). See

http://www.edcallahan.com/web110/lectures/litdigest.htm

(you are probably familiar with the example, but this is posted for onlookers) for an example of a poll with a huge sample size that still got the wrong answer.

For a confidence level of 95% with a confidence interval of 4%, we'd need 584 votes.

I'd imagine there's a lot of science to polling which this calculation probably ignores.

Its a "just for giggles" kind of thing.