General Discussion
In reply to the discussion: And people wonder why I hate pit bulls? [View all]pnwmom
(110,301 posts)sample won't project to the general population.
It might be useful to an individual pet owner as a measure of how well their dog did on the particular test items. But it won't give you valid results for comparing different breeds.
https://methods.sagepub.com/reference/encyclopedia-of-survey-research-methods/n526.xml
Self-selection bias is the problem that very often results when survey respondents are allowed to decide entirely for themselves whether or not they want to participate in a survey. To the extent that respondents' propensity for participating in the study is correlated with the substantive topic the researchers are trying to study, there will be self-selection bias in the resulting data. In most instances, self-selection will lead to biased data, as the respondents who choose to participate will not well represent the entire target population.