A large retirement community provides many activities for its residents. The activity director is considering adding a trivia night on Tuesday evenings if there is enough interest from the residents. To measure interest in the trivia night, the activity director leaves a printed survey in residents’ mailboxes, on which the resident can express whether they are interested. Of the 68 surveys returned, 55 expressed interest. Which of these describes the type of bias in this survey and a likely direction of the bias in estimating overall community support for the trivia night?