Stratified- In general the size of the sample in each stratum is taken in proportion o the size of the stratum. This is called proportional allocation. Suppose that in a company there are the following staff: male, full-time: 90; male, part-time: 18; female, full-time: 9; female, part-time: 63 and we are asked to take a sample of 40 staff, stratified according to the above categories. C. Random-Len a cooking gas bottling plant, thousands of cylinders are filled and dispatched to the outlets every day.
Should there be an inspection from the department of weights and measures, they check by random sampling; taking 5 or 10 cylinders at random and checking the weight or the pressure of the gas in the yielder. D. Systematic-Suppose we have six schools with populations of 150, 180, 200, 220, 260, and 490 students respectively and we want to use student population as the basis for a APS sample of size three. E. Cluster- a study with relatively large square fixed area plots of 50 m x 50 m had been carried out, on which all tree positions were mapped.
Because the individual plots were relatively large, there were only resources available to measure. The small sample size led to a fairly high value of the estimated. F. Multi-stage- Highway 1 55 has a length of 85 miles. Ten of Its 85 one-mile segments were selected and inspected. Two of these segments were rated Excellent. The total cost of urgent repairs on the 10 selected segments was $90,000. II. Non-probably A. Convenience- We visit every household In a given street, and Interview the first person to answer the door.
In any household with more than one occupant, this Is a inviolability sample, because some people are more likely to answer the door (e. G. An unemployed person who spends most of their time at home is more likely to calls) and it’s not practical to calculate these probabilities. B. Purpose- If a researcher is studying the nature of school spirit as exhibited at a school pep rally, he or she might interview people who did not appear to be caught up in the emotions of the crowd or students who did not attend the rally at all.
In this case, the researcher is using a purposive sample because those being interviewed fit a specific purpose or description. C. Quota-Len a study wherein the researcher likes to compare the academic performance of the different high school class levels, its relationship with gender and socioeconomic status, the researcher first identifies the subgroups. Usually, the subgroups are the characteristics or variables of the study.
The researcher divides the entire population into class levels, intersected with gender and socioeconomic status. Then, he takes note of the proportions of these subgroups in the entire population and then samples each subgroup accordingly. D. Extensive- sampling involves enough existing background data to formulate a comprehensive research design. Extensive sampling provides generalizations about large areas. For example, extensive sampling of vegetation might reveal regional patterns.