text: "Census" is a complete count and categorization of a population, where "population" doesn't have to mean just living things. A census of the birds in your backyard is a complete count and categorization of them, and a census of the bills in your dad's "to be paid" box is a complete count and categorization of them.\n\nA "sample" is a selection from a population. You can often tell a lot about a population just by taking a sample. If you stand in your backyard and see 50 birds and 10 of them are robins, you can probably guess that about 1/5 of all the birds in the yard are robins (unless you are just looking at the ground where all the robins are). Statistics is the study of how different kinds of samples can predict characteristics of a population, and to what degree of accuracy.\n\nYou can estimate the total of the bills in the "to be paid" box without adding them all up. If there are 50 bills to be paid, and you pull out 10 of them at random and add them up, the total of all the bills is probably around 5 times the total you got from the sample.