The three big ideas of sampling: examine a part of the whole. Want to know about the population but that is impractical so we examine a sample. Sample survey: ask questions of a small group of people to learn something about the entire population. Bias: sampling methods that tend to over- or underemphasize some characteristics of the population, sampling must be random, randomize. Randomizing: protects us from the influences of all features of our population by making sure that, on average, the sample looks like the rest of the population. The size of the sample, not the population is what matters: a sample of 100 people at a university and 100 in canada are equally, it"s the sample size effecttype equation here. ive. Does a census make sense: census: sample of entire population, can be hard to do impractical, expensive, population changes while you work. Population parameter: a parameter used in a model for a population.