A city planning committee surveys 100 people waiting at a bus stop about the expansion of the public transportation system.
Which is the most appropriate description of this sample?
random sample systematic sample self-selected sample
convenience sample bipartisan sample stratified random sample
Of the options given here, the best choice is to call this a convenience sample. A convenience sample is a sample in which respondents are chosen because it is convenient to interview them. They are chosen, for example, because the respondents are in a place that is easy for the interviewer to work in. In this case, the respondents are chosen because they are at a bus stop. The bus stop is convenient for the researchers because it is a place where people who might be interested in public transportation will gather. That way, the researchers do not have to go out looking for people to survey.
This sample is not in any way randomized. There are many people in the city (those who do not go to that bus stop) who have zero chance of being polled. Therefore, this cannot be a random sample, a stratified random sample, or a systematic sample as all of these are randomized to at least some degree.
The idea of a bipartisan sample has to do with political polling. It does not really apply here.
This is not really a self-selected sample because the respondents did not consciously choose to go to the bus stop in order to take the survey. Instead, they were selected by the researchers. This is the second-best answer, but the best answer is that this is a convenience sample.