How can a sample of 1,000 be representative of a nation with 50 million people? Don you need more for a large country than a small country?
• We start with a sampling frame that is representative of 50 million people, break it down to identify each region and each area of land in that sampling frame, so that each land area accounts for all the people in that region, and each person therefore has an equally random chance of being selected. • The key is ensuring that the selection process is truly random and conducted based on probability. The number of cases over 1,000 doesn’t matter as much as the randomness of the sampling. Twenty thousand cases of literate adults aged 20 to 50 in a solely urban area will not be as representative of a population as are 1,000 cases across a nation that captures urban/rural, young/old, and literate/nonliterate.
