SCI110 Chapter 4

Select all the sampling methods that are random sampling methods.

Simple random sampling
Stratified sampling
Self-selected sampling
Cluster sampling
Multi-stage sampling
Voluntary sampling
Judgement sampling

What is the main advantage of using a random sampling method?

It ensures that the study results are precise.
The sample, and the results obtained from the sample, are likely to well-represent the population.
It makes doing the study easier.
It ensures that the study is internally valid.

A study comparing two new prototype vaccines for malaria recruited a sample of 200 Americans who had contracted malaria.

These recruits were obtained by approaching all patients with a confirmed malaria diagnosis who were admitted to hospitals. Patients were free to volunteer for the study or not. The study was then conducted to a high standard.

Which of the following statements are true?

The stud is likely to have high external validity.
This study is likely to have a high internal validity.
This is a voluntary response sample.
The sample size is too small for the study results to be useful for the general population.