In article ,
Jose wrote:

and there is the problem - can you really estimate or bound the error
from all the error sources (e.g., people not participating or
deliberately lying to the poll)?

Yes.

You cannot "bound" the error in an absolute sense, except to say that it's no
bigger than the total population, which is useless. However, if a poll is
done right, you can estimate the likely error. For example, "95% of the
time, the error will be
less than 1%. 98% of the time, the error will be less than 5%" (I'm making
these numbers up since they depend on how well the poll is conducted, and how
big the sample size is, etc). This is where the standard deviation of the
mean comes in as an
estimate of how good your measurement is.

This is true only if you know the distribution function.

--
Bob Noel