25. A researcher needs a sample of 500 items from a production line. The researcher includes all 50 items from each batch of items in a sample of 10 batches. Which sampling plan is described?
Answer: C
Cluster sampling is described in this scenario.
In this sampling plan, the researcher selects entire batches as clusters, including all items from each of the selected batches to form the sample. This method effectively allows the researcher to gather a representative sample from the production line by focusing on specific groups rather than individual items.
A) Judgment
Judgment sampling involves selecting items based on the researcher’s discretion or expertise rather than a random or systematic method. Since the scenario describes a structured approach where entire batches are sampled, this option does not apply.
B) Systematic
Systematic sampling involves selecting items at regular intervals from a list or sequence. In this case, the researcher is not using a systematic interval but rather selecting entire batches, making this option incorrect.
C) Cluster
Cluster sampling is accurately depicted here as the researcher includes all items from entire batches (clusters) in the sample. This method is particularly useful when dealing with large populations, and the approach described aligns perfectly with the definition of cluster sampling.
D) Stratified
Stratified sampling involves dividing the population into distinct subgroups (strata) and then sampling from each stratum. The researcher in this scenario does not divide the batches into different strata but rather selects whole batches, which makes this option incorrect.
Conclusion
Cluster sampling is the correct answer as it encapsulates the method of selecting complete batches for the sample, which is the primary focus of the sampling plan described. The other options fail to represent the strategy employed by the researcher, either by focusing on individual selection processes or not aligning with the method of selecting entire groups within the population.