13 December 2018 - Remarkably, it does not matter how big the general population, a sample of size of about 400 will give you a margin of error of about 5% or 6%, if the poll is random and the methodology sound. Just to put that in context, because it is a mathematical marvel, if you were able to generate a random sample of 400 people in China (population 1.3-billion), you could generate findings with about a 5% margin of error for the whole of China.
