Soc 5 random sampling methods

• elements of the population are put into
• a list and then every k th element in the list is chosen (systematically) for inclusion. To ensure against bias, the researcher selects the first individual at random.

• PRO: simplicity in randomization, POP is evenly sampled
• CON: can interact with a periodic trait w/in POP (ie, may only have Hispanics and not generalizable to the entire population)

initially categorize subjects into groups (age, socioeconomic status, gender, etc.); then randomly select from the different strata (which do not include any overlaps).

• PRO: used for studying a particular population. Warrants more precise statistical outcomes.
• CON: may require more administrative effort than a simple random sample.

• (used when simple random sampling is almost impossible due to size of population)
• select groups (church), then select individual subjects from each through choice of random sampling.
• Usually population elements already grouped into subpopulations and lists of those subpopulations may already exist or can be easily created.

PRO: Quick, cheap and easy.

• CON: least representative of population for probability sampling.
• Possibly over or underrepresented cluster in terms of characteristics that can skew results of the study.
• Possibly high sampling error caused by the
• limited clusters included in the sample, which leaves a significant proportion of the population unsampled.