Sampling Methods Math Example 4
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Example 4
hardA researcher randomly selects every 10th name from an alphabetical list of 1000 employees. Explain why this is systematic sampling, calculate the starting point needed, and describe a potential bias if the list is alphabetized by department.
Solution
- 1 Systematic sampling: select every th element; sample size =
- 2 Starting point: randomly select a number between 1 and 10 (e.g., 3); then sample elements 3, 13, 23, 33, ...
- 3 Potential bias: if the list is grouped by department (all Accounting employees A01–A50, all Biology B01–B30, etc.), selecting every 10th may systematically favor certain departments or consistently skip others if department sizes are multiples of 10
Answer
Systematic: select every 10th, starting at a random number 1–10. Bias if list has periodic departmental structure.
Systematic sampling is susceptible to periodic bias if the list has a cyclical pattern with the same period as k. A randomly shuffled list before systematic sampling eliminates this bias. Always check list ordering before applying systematic sampling.
About Sampling Methods
Systematic approaches for selecting a subset of individuals from a population. The main probability methods are: simple random sample (SRS), stratified random sample, cluster sample, and systematic sample. Convenience sampling is a non-probability method that is generally biased.
Learn more about Sampling Methods →More Sampling Methods Examples
Example 1 medium
Describe four sampling methods: simple random, stratified, cluster, and systematic. Compare their ad
Example 2 hardA school has 500 students: 200 freshmen, 150 sophomores, 100 juniors, 50 seniors. Design a proportio
Example 3 easyA researcher wants to study opinions of 10,000 employees across 50 departments. She randomly selects