| − | '''Statistical sampling''' is the process of finding a representative portion of a large [[population (statistics)|population]]. In [[quality control]], a percentage of products will be selected at random for testing, and the results ''extrapolated'' to the whole. For example, out of 100,000 [[car]]s produced, 5 will be crash-tested. The results will be assumed to hold for the cars actually sold. | + | '''Statistical sampling''' is the process of finding a representative portion of a large population. In quality control, a percentage of products will be selected at random for testing, and the results ''extrapolated'' to the population. For example, out of 100,000 [[car]]s produced, 30 might be crash-tested. The results will be assumed to hold for the entire population of cars actually sold. |
| − | In [[public opinion]] polls, the people who are contacted must be carefully selected to avoid several kinds of [[selection bias]]. | + | In [[public opinion]] polls, samples must be carefully done in order to avoid several kinds of bias. |