In this lesson, you will learn how to select restaurant samples using four common sampling methods and how to describe each method clearly. Understanding how a sample is chosen matters because the sampling procedure affects how well the sample represents the population.
The population is the complete group you want to study. In this activity, it is all the restaurants in the table. A sample is the subset selected for investigation, and the sampling frame is the list or organized set of population members from which the sample is drawn.
All flashcards
What is a sampling frame?
A complete list or organized set of population members from which a sample is drawn. Here, the 85 restaurant entries form the sampling frame.
What is simple random sampling?
A method that selects individuals by chance so every possible sample of the specified size has an equal chance of being chosen. Numbering the restaurants and drawing distinct numbers is one way to do it.
How does systematic sampling work?
Arrange the population in a fixed order, choose a random starting point, and then select entries at regular intervals. With 85 restaurants and a target of 15, the spacing is about 5.67 entries.
How are stratified and cluster sampling different?
Stratified sampling takes a sample from every stratum. Cluster sampling randomly selects some clusters and includes every member of those selected clusters.
What rounding issue occurs in the restaurant activity?
Rounding 25% of each city stratum independently gives 21 restaurants, not 20; rounding 25% of each entree-cost stratum gives 22, not 21. An exact requested total may require an instructed quota adjustment.
Quiz questions
What is a sampling frame?Answer: The complete list or organized set of population members from which a sample is drawn.
What property defines a simple random sample of a specified size?Answer: Every possible sample of that size has an equal chance of selection.
What makes a sample systematic?Answer: It selects entries at regular intervals after a random starting point.
In a city-stratified sample, how are restaurants selected?Answer: Each city is treated as a stratum, and restaurants are randomly selected within every city.
How is a cluster sample drawn from two cities?Answer: Randomly choose two cities and include every restaurant in both.
Based on Introductory Statistics 2e by Barbara Illowsky, Susan Dean (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.