haphazard sampling
any method of selecting research participants that is neither random nor systematic and hence is likely to be biased. Convenience sampling is an example. Thus, if researchers decided to solicit participants from an Internet advertisement the process would be biased toward individuals who own a computer and who are more likely to respond to computer-based communications. Depending on the prevalence and likelihood of computer use in various facets of the population, the sample could be biased by gender, ethnicity, geographical location, economic status, or age, among other possible variables.