Sampling Techniques
Sampling Techniques are ways to choose a small group from a larger population to study. They help researchers make sure the small group reflects the larger population, so they can draw accurate conclusions.
A population refers to the entire group of individuals or items being studied whereas a sample refers to a smaller group selected from the population to gather information.Studying the whole population is often too difficult, so researchers analyze a sample instead.
Sampling Techniques
- Simple Random Sampling: Every individual has an equal chance of being chosen
- Systematic Sampling: Selecting every \(n\)th person from a list
- Stratified Sampling: Dividing the population into groups and picking a proportional number from each
- Cluster Sampling:: Selecting entire groups instead of individuals
- Multi-Stage Sampling: Using multiple random selection steps
- Voluntary-Response Sampling: Participants choose to respond, leading to potential bias
- Convenience Sampling: Selecting people who are easy to reach
The formula for systematic sampling is:
Surveys & Types of Surveys
A survey is a way to collect information from people. Different types include:
- Questionnaires: Written sets of questions (paper or online).
- Interviews: Asking people questions in person or over the phone.
- Online Surveys:: Collecting responses via websites or apps.
- Telephone Surveys: Calling individuals to gather responses.
- Mail Surveys: Sending and receiving answers via postal mail.
Surveys help researchers understand opinions and trends, and the right method depends on study goals, cost, and accessibility.
Who should be the next captain of the soccer team?
All players on the soccer team.
Who should be the next class representative for the student body?
All students in the class.
What is your favorite pizza topping?
All individuals who have an opinion about pizza toppings.
Which superhero movie is the best?
All people who watch superhero movies.
How effective is the new remote learning app?
All users of the new remote learning app.
A newspaper invites its readers to submit their opinions on the new city park project.
Voluntary Response Sampling. Readers voluntarily submit their opinions, meaning the sample is based on those who choose to respond.
A university department randomly selects students from various academic programs, ensuring each program is represented equally.
Stratified Sampling. The population is divided into different strata (academic programs), and individuals are randomly selected from each group.
A reporter interviews people at a busy shopping mall to get their opinion on a new fashion trend.
Convenience Sampling. The reporter interviews people who are easy to access (those at the mall), not necessarily a random sample.
A manager surveys every tenth employee listed on the company's payroll.
Systematic Sampling. The manager selects every tenth employee from a list.
A market researcher first selects 10 cities randomly, then 3 stores from each city, and finally 5 shoppers from each store.
Multi-Stage Sampling. This involves selecting multiple groups at different stages (cities, stores, and shoppers).