The president of an agency specializing in public opinion surveys claims that approximately 70% of all people to whom the agency sends questionnaires responds by filling out an returning the questionnaire. Four such questionnaires are sent out. Let r be the number of questionnaires that are filled out and returned.
What is the probability that exactly three questionnaires are filled out and returned?
What is the probability that at least three questionnaires are filled out and returned?
What is the probability that no questionnaires are filled out and returned?