ABSTRACT
When researchers use the data collected from samples to make inferences about the population (or populations) from which the samples were selected, they need to have some way of deciding how meaningful the sample data are. Are the differences between two samples (e.g., a group of adults from Alaska and a group of adults from New York) in their average levels of happiness large enough to conclude that the populations of adults from these two states actually differ in how happy they are? Is the relationship between years of education and income among a sample of 50 American adults strong enough to determine that income is related to education in the larger population of American adults? How do researchers reach important conclusions about how well sample statistics generalize to the larger population?
