Full Answer Section

However, even with random sampling, it is still possible to have some volunteer bias. This is because the sampling frame may not be representative of the general population. For example, if the sampling frame is based on a list of people who have signed up for a research newsletter, then the participants will be more likely to be interested in research and may not be representative of the general population.

To further reduce volunteer bias, researchers can use other techniques, such as:

Recruiting participants from a variety of sources. This includes recruiting from both traditional and non-traditional sources, such as community organizations, social media, and public places.
Offering incentives for participation. This can help to motivate people to participate, even if they are not initially interested in the research.
Protecting the confidentiality of participants. This can help to build trust and encourage people to participate.
It is important to note that no method can completely eliminate volunteer bias. However, by using random sampling and other techniques, researchers can reduce volunteer bias and improve the representativeness of their samples.

To answer your specific question, yes, random sampling still only includes volunteers. However, it is a more representative sample of volunteers than other methods, such as convenience sampling.