suppose you want to know how often people brush their teeth

suppose you want to know how often people brush their teeth everyday. so you take a survey , explain why the results would indicate far more gleeming smiles than than exactually would exist

Solution

This question may create biased answers, people tend to conceal embarrasing truths, and might lie about their habits. Further, people tend to be optimistic about themselves, they might think they are telling the truth, but might infact overestimate their frequencies.