Cian
Well-known member
The statistics would say that to be 95% confident that the result is within 5 percentage points of the total 25,000 population's view then you'd need a sample size of 378.
To be 99% confident you'd need a sample of 648.
www.surveysystem.com/sscalc.htm
Needs correction for sampling bias, though.
People definitely misunderstand the numbers required for opinion polling though - I know someone who was astounded they'd never been phone polled for an election because "they must need to ask tens of thousands". In a country with about 2M registered voters!