Can 500 people, or 1,000 people, or even 1,500 people, represent all Americans?
Yes – according to statistical and probability theory – if the right methods are used to choose the sample of people. Stripped of statistics-speak, sampling the population is like testing the temperature of a bowl of soup – you don’t need to eat the whole thing, just stir it up and taste a spoonful or two. Or like taking a blood sample – no need to drain the patient dry, a syringe-ful will do. One key element of probability sampling, as noted above, is that poll respondents must be chosen randomly. Each adult in the population should also have an equal chance of being included in the poll.
