> So, doesn't that just mean that a statistically significant portion of the regular HN users would have to respond?
No. If 50% of HN visitors voted but 99% of those over 40 didn't (due to whatever confounding factor you like - say embarrasment), you'd still wouldn't be able to extrapolate from the sample to the category of "HN visitors".
Re:Poll: How old are you?
by tokenadult on Sunday March 15, 2009 @06:41PM
(#517351)
Correct. It doesn't matter how large a sample size is if the sample is biased. This should be something that every high school student knows after any high school statistics course, but it is a crucial consideration that is widely ignored.
Re:Poll: How old are you?
by whatusername on Monday March 16, 2009 @10:25AM
(#518182)
although we can all think of an edge case.. (especially if we know how the sample is biased)
eg: a gender survey in the general population that transgender respondees do not answer -- ends up with a 99% sample size (all but the transgenders) -- and thus gives a pretty significant bit of data on male:female ratios, etc..
Agreed in principle though.
Of course, you'd have to figure out how to define "regular HN users" and what would be a significant portion of them.
If this poll were to get that much response, it would also tell you something interesting: that HN users respond to polls in statistically significant numbers :)
So, voluntary response polls are not worthless if enough people voluntarily respond to them, but this is a tricky problem.