Sources of Errors in Polls
So if one makes a poll, the error comes from two sources – the so-called statistical error and the so-called bias.
- The bias is like we discussed above – one must choose a representative subset of the voters.
- The reason why one chooses some 1000 people to poll, is that this will give statistical errors of around 2% and the quoted errors combine this with errors due to a biased sample.
There is not much point in using more 1000 or so in a poll as you will decrease the statistical error but it will be hard to decrease the overall error much more.