IBM SPSS COMPLEX SAMPLES 19 manual Sampling Wizard Sampling Method

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Chapter 2

Sampling Wizard: Sampling Method

Figure 2-3

Sampling Wizard, Sampling Method step

This step allows you to specify how to select cases from the active dataset.

Method. Controls in this group are used to choose a selection method. Some sampling types allow you to choose whether to sample with replacement (WR) or without replacement (WOR). See the type descriptions for more information. Note that some probability-proportional-to-size (PPS) types are available only when clusters have been defined and that all PPS types are available only in the first stage of a design. Moreover, WR methods are available only in the last stage of a design.

„Simple Random Sampling. Units are selected with equal probability. They can be selected with or without replacement.

„Simple Systematic. Units are selected at a fixed interval throughout the sampling frame (or strata, if they have been specified) and extracted without replacement. A randomly selected unit within the first interval is chosen as the starting point.

„Simple Sequential. Units are selected sequentially with equal probability and without replacement.

„PPS. This is a first-stage method that selects units at random with probability proportional to size. Any units can be selected with replacement; only clusters can be sampled without replacement.