| A | B |
|---|
| Cross-Sectional | data are observed, measured, and collected at one point in time, not over a period of time |
| Retrospective | data are collected from a past time period by going back in time |
| Prospective | data are collected in the future from groups that share common factors |
| Permutations | arranged in which different sequences of the same items are counted separately - order matters |
| Combinations | arrangements in which different sequences of the same items are not counted separately - order does not matter |
| Systematic | select some starting point, then select every nth element in the population |
| Convenience | use results that are easy to get |
| Stratified | subdivide population into at least two different sub-groups so that subjects in the same group share the same characterjistics, then draw a sample from each subgroup |
| Cluster | divide population into sections, then randomly select some of those clusters, and then choose all members from selected groups |
| Random | each member of the population has an equal chance of being selected - computers are often used to generate numbers |
| Simple Random | selection n of which every possible sample of the same size n has the same chance of being chosen |
| Sampling Error | occurs when the sample has been selected with a random method, but there is a discrepancy b/w a sample result and the true pop. result; such an error results from chance sample fluctuations |
| Non-Sampling Error | the result of human error, including such factors as wrong data entries, computing errors, questions with biased wording, false data provided by respondents, forming biased conclusions, or applying statistical methods that are not appropriate for the circumstances |
| Nominal | consists of names, labels, or categories; cannot be arranged in ordering scheme |
| Ordinal | can be arranged in order, but differences b/w data values either cannot be determined or are meaningless |
| Interval | can arrange in order; differences can be found and are meaningful; no natural zero starting point at which none of the quantity is present |
| Ratio | can arrange in order; differences can be found and are meaningful; there is a natural starting point; zero indicates that none of the quantity is present |
| Continuous | result from infinitely many possible quantitative values, where the collection is not countable (ex: time and weight) |
| Discrete | result when the data values are quantitative and the number of values is finite or "countable" |
