Sampling Methods

What is the main purpose of using a sample in research?

• To include all members of the target population

• To save time and resources

• To avoid conducting research

• To ensure bias in results

Answer explanation

The main purpose of using a sample in research is to save time and resources. It allows researchers to gather data from a smaller group rather than including all members of the target population, making the process more efficient.

Which sampling method ensures every member of the target population has an equal chance of being selected?

• Systematic sample

• Stratified sample

• Random sample

• Volunteer sample

Answer explanation

A random sample ensures that every member of the target population has an equal chance of being selected, making it the most unbiased sampling method compared to systematic, stratified, or volunteer sampling.

What is a key disadvantage of a random sample?

• It is time-consuming

• It may not be representative

• It is biased

• It is expensive

Answer explanation

A key disadvantage of a random sample is that it may not be representative of the entire population, leading to skewed results. This can occur if certain groups are underrepresented or overrepresented in the sample.

In a systematic sample, how is the sample selected?

• By using a computer program

• By selecting every nth person

• By asking for volunteers

• By dividing into subgroups

Answer explanation

In a systematic sample, individuals are selected at regular intervals, specifically by choosing every nth person from a list. This method ensures a representative sample without bias, unlike the other options.

What is a stratified sample designed to do?

• Include only volunteers

• Represent the entire population

• Reflect the proportions of subgroups

• Select every nth person

Answer explanation

A stratified sample is designed to reflect the proportions of subgroups within a population, ensuring that each subgroup is adequately represented in the sample. This helps improve the accuracy of the results.

Which sampling method is least costly in terms of time and money?

• Random sample

• Systematic sample

• Opportunity sample

• Stratified sample

Answer explanation

The opportunity sample is the least costly method as it involves selecting individuals who are readily available, saving both time and money compared to more structured sampling methods like random or stratified sampling.

What is a major drawback of opportunity sampling?

• It is time-consuming

• It may not represent the target population

• It requires a list of the population

• It is expensive

Answer explanation

A major drawback of opportunity sampling is that it may not represent the target population. This can lead to biased results, as the sample may not reflect the diversity or characteristics of the entire population.

What is a volunteer sample also known as?

• Self-selection

• Random selection

• Systematic selection

• Stratified selection

Answer explanation

A volunteer sample is also known as self-selection because participants choose to join the study on their own, rather than being randomly selected or systematically chosen.

Which sampling method requires minimal input from the researcher?

• Systematic sample

• Stratified sample

• Volunteer sample

• Random sample

Answer explanation

A volunteer sample requires minimal input from the researcher, as participants self-select to be part of the study. In contrast, systematic, stratified, and random samples involve more planning and selection criteria.

What is a potential issue with volunteer samples?

• They are always representative

• They require a list of the population

• They may attract a certain 'profile' of person

• They are time-consuming

Answer explanation

Volunteer samples may attract a certain 'profile' of person, leading to bias. This can result in a lack of diversity in the sample, making it unrepresentative of the broader population.