What of these would probably occur from under-coverage?

Under-coverage occurs when certain groups within a population are inadequately represented in a survey or study, leading to biased results. This can result in skewed data that does not accurately reflect the views or behaviors of the entire population. Consequently, important insights may be missed, and policies or decisions made based on the findings could be ineffective or harmful, as they do not account for the perspectives of the underrepresented groups.