Basic terms and concepts in sampling

 sampling is a fundamental concept in statistics that allows us to draw inferences about a large group (population) by studying a smaller, manageable group (sample).

• Statistical Population: This is the entire collection of individuals or items we're interested in studying. It could be all the students in a school, all the customers of a company, or all the tomatoes grown in a specific region.

• Sample: This is a subset of the population that is chosen to represent the whole. We use samples because studying the entire population can be impractical or impossible. The accuracy of our inferences depends on how well the sample reflects the population.

• Sampling Frame: This is a list or database that identifies all the members of the population. It serves as the source from which we select the sample. An ideal sampling frame includes everyone in the target population and avoids duplicates.

• Sampling Error: This is the discrepancy between a sample statistic (e.g., average income in the sample) and the corresponding population parameter (e.g., average income in the population). Sampling error is inevitable, but we can minimize it by using good sampling techniques and increasing the sample size.

• Sample Size: This refers to the number of individuals or items selected from the population. There's a trade-off between sample size and cost/effort. Larger samples generally lead to lower sampling errors but require more resources to collect and analyze.

• Non-Response: This occurs when potential participants in a study (e.g., survey) choose not to respond. Non-response can introduce bias if those who don't respond differ systematically from those who do. Researchers try to minimize non-response through reminders and incentives.