In research terms, a convenience sample is a group of folks who feature in a study because—well, they happened to be there. Convenience samples do not permit truly random assignments of individuals into the cohorts being studied. For this reason, it is impossible to apply the study results to the general population, or to make claims about statistical significance.

https://www.arts.gov/stories/blog/2021/sampling-beats-and-youth-research-participants-real-time?utm_source=SM&utm_medium=TW&utm_campaign=BLOG_JuneMeasureforMeasure_TW